Method for Controlling End Effector Closure for Powered Surgical Stapler

ABSTRACT

A powered surgical stapler includes a motor unit, a movable member, a controller, a sensor assembly, an anvil, and an opposing deck surface. A method of operating the stapler includes controlling the motor unit to actuate the movable member to move from the open position towards the closed position. The method also includes sensing closure data using the sensor assembly. The closure data includes an initial tissue contact position, a gap formed between the anvil and the opposing deck surface, and an axial force on the anvil. The method also includes communicating the closure data to the controller. The method also includes determining at least one of an adjusted closure rate or an adjusted closure stroke using the closure data. The method also includes controlling the motor unit using at least one of the adjusted closure rate or the adjusted closure stroke.

BACKGROUND

In some surgical procedures (e.g., colorectal, bariatric, thoracic,etc.), portions of a patient's digestive tract (e.g., thegastrointestinal tract and/or esophagus, etc.) may be cut and removed toeliminate undesirable tissue or for other reasons. Once the tissue isremoved, the remaining portions of the digestive tract may be coupledtogether in an end-to-end anastomosis, an end-to-side anastomosis, or aside-to-side anastomosis. The anastomosis may provide a substantiallyunobstructed flow path from one portion of the digestive tract to theother portion of the digestive tract, without also providing any kind ofleaking at the site of the anastomosis.

One example of an instrument that may be used to provide an anastomosisis a circular stapler. Some such staplers are operable to clamp down onlayers of tissue, cut through the clamped layers of tissue, and drivestaples through the clamped layers of tissue to substantially seal thelayers of tissue together near the severed ends of the tissue layers,thereby joining the two severed ends of the anatomical lumen together.The circular stapler may be configured to sever the tissue and seal thetissue substantially simultaneously. For instance, the circular staplermay sever excess tissue that is interior to an annular array of staplesat an anastomosis, to provide a substantially smooth transition betweenthe anatomical lumen sections that are joined at the anastomosis.Circular staplers may be used in open procedures or in endoscopicprocedures. In some instances, a portion of the circular stapler isinserted through a patient's naturally occurring orifice.

Examples of circular staplers are described in U.S. Pat. No. 5,205,459,entitled “Surgical Anastomosis Stapling Instrument,” issued Apr. 27,1993; U.S. Pat. No. 5,271,544, entitled “Surgical Anastomosis StaplingInstrument,” issued Dec. 21, 1993; U.S. Pat. No. 5,275,322, entitled“Surgical Anastomosis Stapling Instrument,” issued Jan. 4, 1994; U.S.Pat. No. 5,285,945, entitled “Surgical Anastomosis Stapling Instrument,”issued Feb. 15, 1994; U.S. Pat. No. 5,292,053, entitled “SurgicalAnastomosis Stapling Instrument,” issued Mar. 8, 1994; U.S. Pat. No.5,333,773, entitled “Surgical Anastomosis Stapling Instrument,” issuedAug. 2, 1994; U.S. Pat. No. 5,350,104, entitled “Surgical AnastomosisStapling Instrument,” issued Sep. 27, 1994; and U.S. Pat. No. 5,533,661,entitled “Surgical Anastomosis Stapling Instrument,” issued Jul. 9,1996; and U.S. Pat. No. 8,910,847, entitled “Low Cost Anvil Assembly fora Circular Stapler,” issued Dec. 16, 2014. The disclosure of each of theabove-cited U.S. Patents is incorporated by reference herein.

Some circular staplers may include a motorized actuation mechanism.Examples of circular staplers with motorized actuation mechanisms aredescribed in U.S. Pub. No. 2015/0083772, entitled “Surgical Stapler withRotary Cam Drive and Return,” published Mar. 26, 2015; U.S. Pub. No.2015/0083773, entitled “Surgical Stapling Instrument with Drive AssemblyHaving Toggle Features,” published Mar. 26, 2015; U.S. Pub. No.2015/0083774, entitled “Control Features for Motorized Surgical StaplingInstrument,” published Mar. 26, 2015; and U.S. Pub. No. 2015/0083775,entitled “Surgical Stapler with Rotary Cam Drive,” published Mar. 26,2015. The disclosure of each of the above-cited U.S. Patent Publicationsis incorporated by reference herein.

While various kinds of surgical stapling instruments and associatedcomponents have been made and used, it is believed that no one prior tothe inventor(s) has made or used the invention described in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims which particularly pointout and distinctly claim this technology, it is believed this technologywill be better understood from the following description of certainexamples taken in conjunction with the accompanying drawings, in whichlike reference numerals identify the same elements and in which:

FIG. 1 depicts a perspective view of an exemplary circular surgicalstapler;

FIG. 2 depicts a perspective view of the circular stapler of FIG. 1,with a battery pack removed from a handle assembly and an anvil removedfrom a stapling head assembly;

FIG. 3 depicts a perspective view of the anvil of the circular staplerof FIG. 1;

FIG. 4 depicts a perspective view of the stapling head assembly of thecircular stapler of FIG. 1;

FIG. 5 depicts an exploded perspective view of the stapling headassembly of FIG. 4;

FIG. 6 depicts an exploded perspective view of the circular stapler ofFIG. 1, with portions of the shaft assembly shown separated from eachother;

FIG. 7A depicts a cross-sectional side view of the anvil of FIG. 3positioned within a first section of a digestive tract and the staplinghead assembly of FIG. 4 positioned in a second section of the digestivetract, with the anvil separated from the stapling head assembly;

FIG. 7B depicts a cross-sectional side view of the anvil of FIG. 3positioned within the first section of the digestive tract and thestapling head assembly of FIG. 4 positioned in the second section of thedigestive tract, with the anvil secured to the stapling head assembly;

FIG. 7C depicts a cross-sectional side view of the anvil of FIG. 3positioned within the first section of the digestive tract and thestapling head assembly of FIG. 4 positioned in the second section of thedigestive tract, with the anvil retracted toward the stapling headassembly to thereby clamp tissue between the anvil and the stapling headassembly;

FIG. 7D depicts a cross-sectional side view of the anvil of FIG. 3positioned within the first section of the digestive tract and thestapling head assembly of FIG. 4 positioned in the second section of thedigestive tract, with the stapling head assembly actuated to sever andstaple the clamped tissue;

FIG. 7E depicts a cross-sectional side view of the first and secondsections of the digestive tract of FIG. 7A joined together at anend-to-end anastomosis;

FIG. 8 depicts a perspective view of a user interface feature of thehandle assembly of the circular stapler of FIG. 1;

FIG. 9 depicts a perspective view of another exemplary circular surgicalstapler;

FIG. 10 depicts a schematic view of the circular stapler of FIG. 9,including a control system of the circular surgical stapler;

FIG. 11 depicts a diagrammatic view of an exemplary method forcontrolling the circular stapler of FIG. 9 via the control system ofFIG. 10;

FIG. 12 depicts a diagrammatic view of an exemplary method forcalibrating closure rate and closure stroke of a movable member of thecircular stapler of FIG. 9 by adjusting actuation algorithms executed bythe control system of FIG. 10;

FIG. 13 depicts a schematic side cross-sectional view of the staplinghead assembly and the anvil of the circular stapler of FIG. 9operatively coupled with the control system of FIG. 10, where first andsecond tissue layers are disposed between the trocar and the decksurface;

FIG. 14 depicts a line graph showing exemplary relationships betweenoperational elements of the circular stapler of FIG. 9 over time,including anvil displacement, knife displacement, and firing load on themotor unit;

FIG. 15A depicts a diagrammatic view of a first portion of anotherexemplary method for controlling the circular stapler of FIG. 9 byadjusting actuation algorithms executed by the control system of FIG.10; and

FIG. 15B depicts a diagrammatic view of a second portion of theexemplary method for controlling the circular stapler of FIG. 15A.

The drawings are not intended to be limiting in any way, and it iscontemplated that various embodiments of the technology may be carriedout in a variety of other ways, including those not necessarily depictedin the drawings. The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the presenttechnology, and together with the description serve to explain theprinciples of the technology; it being understood, however, that thistechnology is not limited to the precise arrangements shown.

DETAILED DESCRIPTION

The following description of certain examples of the technology shouldnot be used to limit its scope. Other examples, features, aspects,embodiments, and advantages of the technology will become apparent tothose skilled in the art from the following description, which is by wayof illustration, one of the best modes contemplated for carrying out thetechnology. As will be realized, the technology described herein iscapable of other different and obvious aspects, all without departingfrom the technology. Accordingly, the drawings and descriptions shouldbe regarded as illustrative in nature and not restrictive.

For clarity of disclosure, the terms “proximal” and “distal” are definedherein relative to a surgeon, or other operator, grasping a surgicalinstrument having a distal surgical end effector. The term “proximal”refers to the position of an element arranged closer to the surgeon, andthe term “distal” refers to the position of an element arranged closerto the surgical end effector of the surgical instrument and further awayfrom the surgeon. Moreover, to the extent that spatial terms such as“top,” “bottom,” “upper,” “lower,” “vertical,” “horizontal,” or the likeare used herein with reference to the drawings, it will be appreciatedthat such terms are used for exemplary description purposes only and arenot intended to be limiting or absolute. In that regard, it will beunderstood that surgical instruments such as those disclosed herein maybe used in a variety of orientations and positions not limited to thoseshown and described herein.

I. Overview of Exemplary Circular Surgical Stapling Instrument

FIGS. 1-2 depict an exemplary circular surgical stapling instrument (10)that may be used to provide an end-to-end, side-to-side, or end-to-sideanastomosis between two sections of an anatomical lumen such as aportion of a patient's digestive tract. Instrument (10) of this exampleincludes a body assembly (e.g. a handle assembly (100)), a shaftassembly (200) extending distally from handle assembly (100), a staplinghead assembly (300) at a distal end of shaft assembly (200), and ananvil (400) configured to releasably couple and cooperate with staplinghead assembly (300) to clamp, staple, and cut tissue. Instrument (10)further includes a removable battery pack (120) operable to provideelectrical power to a motor (160) housed within handle assembly (100),as will be described in greater detail below.

Shaft assembly (200) extends distally from handle assembly (100) andincludes a preformed bend. In some versions, the preformed bend isconfigured to facilitate positioning of stapling head assembly (300)within a patient's colon. Various suitable bend angles or radii that maybe used will be apparent to those of ordinary skill in the art in viewof the teachings herein. In some other versions, shaft assembly (200) isstraight, such that shaft assembly (200) lacks a preformed bend. Variousexemplary components that may be incorporated into shaft assembly (200)will be described in greater detail below.

Stapling head assembly (300) is located at the distal end of shaftassembly (200). As shown in FIGS. 1-2 and as will be described ingreater detail below, anvil (400) is configured to removably couple withshaft assembly (200), adjacent to stapling head assembly (300). As willalso be described in greater detail below, anvil (400) and stapling headassembly (300) are configured to cooperate to manipulate tissue in threeways, including clamping the tissue, cutting the tissue, and staplingthe tissue. A knob (130) at the proximal end of handle assembly (100) isrotatable relative to casing (110) to provide precise clamping of thetissue between anvil (400) and stapling head assembly (300). When asafety trigger (140) of handle assembly (100) is pivoted away from afiring trigger (150) of handle assembly (100), firing trigger (150) maybe actuated to thereby provide cutting and stapling of the tissue.

A. Exemplary Anvil

As best seen in FIG. 3, anvil (400) of the present example comprises ahead (410) and a shank (420). Head (410) includes a proximal surface(412) that defines a plurality of staple forming pockets (414). Stapleforming pockets (414) are arranged in two concentric annular arrays inthe present example. In some other versions, staple forming pockets(414) are arranged in three or more concentric annular arrays. Stapleforming pockets (414) are configured to deform staples as the staplesare driven into staple forming pockets (414). For instance, each stapleforming pocket (414) may deform a generally “U” shaped staple into a “B”shape as is known in the art. Proximal surface (412) terminates at aninner edge (416), which defines an outer boundary of an annular recess(418) surrounding shank (420).

Shank (420) defines a bore (422) and includes a pair of pivoting latchmembers (430). Latch members (430) are positioned within bore (422) suchthat distal ends (434) are positioned at the proximal ends of lateralopenings (424), which are formed through the sidewall of shank (420).Lateral openings (424) thus provide clearance for distal ends (434) andlatch shelves (436) to deflect radially outwardly from the longitudinalaxis defined by shank (420). However, latch members (430) are configuredto resiliently bias distal ends (434) and latch shelves (436) to pivotradially inwardly toward the longitudinal axis defined by shank (420).Latch members (430) thus act as retaining clips. This allows anvil (400)to be removably secured to an actuatable closure member in the form of atrocar (330) of stapling head assembly (300), as will be described ingreater detail below. It should be understood, however, that latchmembers (436) are merely optional. Anvil (400) may be removably securedto trocar (330) using any other suitable components, features, ortechniques.

B. Exemplary Stapling Head Assembly

As best seen in FIGS. 4 and 5, stapling head assembly (300) of thepresent example is coupled to a distal end of shaft assembly (200) andcomprises a body member (310) and a staple driver member (350) slidablyhoused therein. Body member (310) includes a distally extendingcylindraceous inner core member (312). Body member (310) is fixedlysecured to an outer sheath (210) of shaft assembly (200), and bodymember (310) and outer sheath (210) thus serve together as a mechanicalground for stapling head assembly (300). In some versions, stapling headassembly (300) may be configured to releasably couple with the distalend of shaft assembly (200), for example as disclosed in U.S. Pat. No.9,597,081, entitled “Motor Driven Rotary Input Circular Stapler withModular End Effector,” issued Mar. 21, 2017, the disclosure of which isincorporated by reference herein.

Trocar (330) is positioned coaxially within inner core member (312) ofbody member (310). As will be described in greater detail below, trocar(330) is operable to translate distally and proximally relative to bodymember (310) in response to rotation of knob (130) relative to casing(110) of handle assembly (100). Trocar (330) comprises a shaft (332) anda head (334). Head (334) includes a pointed tip (336) and an inwardlyextending proximal surface (338). Shaft (332) thus provides a reducedouter diameter just proximal to head (334), with surface (338) providinga transition between that reduced outer diameter of shaft (332) and theouter diameter of head (334). While tip (336) is pointed in the presentexample, tip (336) is not sharp. Tip (336) will thus not easily causetrauma to tissue due to inadvertent contact with tissue. Head (334) andthe distal portion of shaft (332) are configured for insertion in bore(422) of anvil (400). Proximal surface (338) and latch shelves (436)have complementary positions and configurations such that latch shelves(436) engage proximal surface (338) when shank (420) of anvil (400) isfully seated on trocar (330). Anvil (400) is thus secured to trocar(330) through a snap fit provided by latch members (430).

Staple driver member (350) is operable to actuate longitudinally withinbody member (310) in response to activation of motor (160) as will bedescribed in greater detail below. Staple driver member (350) of thepresent example includes two distally presented concentric annulararrays of staple drivers (352). Staple drivers (352) are arranged tocorrespond with the arrangement of staple forming pockets (414) of anvil(400). Thus, each staple driver (352) is configured to drive acorresponding staple into a corresponding staple forming pocket (414)when stapling head assembly (300) is actuated. It should be understoodthat the arrangements of staple drivers (352) and staple forming pockets(414) shown herein may be modified in any suitable manner, provided thatstaple drivers (352) and staple forming pockets (414) are configured toalign with one another to provide proper formation of staples. Stapledriver member (350) also defines a bore (354) that is configured tocoaxially receive core member (312) of body member (310). An annulararray of studs (356) project distally from a distally presented surfacesurrounding bore (354).

A cylindraceous knife member (340) is coaxially positioned within stapledriver member (350). Knife member (340) includes a distally presented,sharp circular cutting edge (342). Knife member (340) is sized such thatknife member (340) defines an outer diameter that is smaller than thediameter defined by the inner annular array of staple drivers (352).Knife member (340) also defines an opening that is configured tocoaxially receive core member (312) of body member (310). An annulararray of openings (346) formed in knife member (340) is configured tocomplement the annular array of studs (356) of staple driver member(350), such that knife member (340) is fixedly secured to staple drivermember (350) via studs (356) and openings (346). By way of example only,studs (356) may be heat staked to knife member (340) using techniquesknown in the art. Other suitable structural relationships between knifemember (340) and stapler driver member (350) will be apparent to thoseof ordinary skill in the art in view of the teachings herein.

A deck member (320) is fixedly secured to a distal end of body member(310). Deck member (320) includes a distally presented deck surface(322) defining two concentric annular arrays of staple openings (324).Staple openings (324) are arranged to correspond with the arrangement ofstaple drivers (352) and staple forming pockets (414) described above.Thus, each staple opening (324) is configured to provide a path for acorresponding staple driver (352) to drive a corresponding staplethrough deck member (320) and into a corresponding staple forming pocket(414) when stapling head assembly (300) is actuated. It should beunderstood that the arrangement of staple openings (324) may be modifiedto correspond with the arrangement of drivers (352) and staple formingpockets (414) described above. It should also be understood that variousstructures and techniques may be used to contain staples within staplinghead assembly (300) before stapling head assembly (300) is actuated.Such structures and techniques that are used to contain staples withinstapling head assembly (300) may prevent the staples from inadvertentlyfalling out through staple openings (324) before stapling head assembly(300) is actuated. Various suitable forms that such structures andtechniques may take will be apparent to those of ordinary skill in theart in view of the teachings herein.

As best seen in FIG. 9, deck member (320) defines an inner diameter thatis just slightly larger than the outer diameter defined by knife member(340). Deck member (320) is thus configured to allow knife member (340)to translate distally to a point where cutting edge (342) is distal todeck surface (322).

In some versions of instrument (10) it may desirable to provideinstrument (10) with features that are configured to indicate properand/or improper attachment of anvil (400) to trocar (330) of staplinghead assembly (300). For instance, if anvil (400) is not properlyattached to trocar (330), an operator may receive audible and/or tactilefeedback indicating improper attachment. Additionally, if anvil (400) isproperly attached to trocar (330), an operator may receive audible,tactile, and/or visible feedback indicating proper attachment. Inaddition, or in the alternative, features may be configured to preventfiring of stapling head assembly (300) unless anvil (400) is properlyattached to trocar (330). For instance, if anvil (400) is not properlyattached to trocar (330), stapling head assembly (300) may be preventedfrom firing. If anvil (400) is properly attached to trocar (330), firingof stapling head assembly (300) may be enabled. Such features mayinclude various types of visual indicia, sensors, switches, and thelike. By way of example only, such features may include those of thetype disclosed in U.S. Pat. No. 10,307,157, entitled “Surgical Staplerwith Anvil Seating Detection,” issued Jun. 4, 2019, and U.S. Pub. No.2017/0258471, entitled “Methods and Systems for Performing CircularStapling,” published Sep. 14, 2017, the disclosures of which areincorporated by reference herein.

C. Exemplary Shaft Assembly

FIG. 6 shows various components of shaft assembly (200), which couplescomponents of stapling head assembly (300) with components of handleassembly (100). In particular, and as noted above, shaft assembly (200)includes an outer sheath (210) that extends between handle assembly(100) and body member (310). In the present example, outer sheath (210)is rigid and includes a preformed curved section as noted above.

Shaft assembly (200) further includes a trocar actuation rod (220) and atrocar actuation band assembly (230). The distal end of trocar actuationband assembly (230) is fixedly secured to the proximal end of trocarshaft (332). The proximal end of trocar actuation band assembly (230) isfixedly secured to the distal end of trocar actuation rod (220). Itshould therefore be understood that trocar (330) will translatelongitudinally relative to outer sheath (210) in response to translationof trocar actuation band assembly (230) and trocar actuation rod (220)relative to outer sheath (210). Trocar actuation band assembly (230) isconfigured to flex such that trocar actuation band assembly (230) mayfollow along the preformed curve in shaft assembly (200) as trocaractuation band assembly (230) is translated longitudinally relative toouter sheath (210). However, trocar actuation band assembly (230) hassufficient column strength and tensile strength to transfer distal andproximal forces from trocar actuation rod (220) to trocar shaft (332).Trocar actuation rod (220) is rigid. A clip (222) is fixedly secured totrocar actuation rod (220) and is configured to cooperate withcomplementary features within handle assembly (100) to prevent trocaractuation rod (220) from rotating within handle assembly (100) whilestill permitting trocar actuation rod (220) to translate longitudinallywithin handle assembly (100). Trocar actuation rod (220) furtherincludes a coarse helical threading (224) and a fine helical threading(226).

Shaft assembly (200) further includes a stapling head assembly driver(240) that is slidably received within outer sheath (210). The distalend of stapling head assembly driver (240) is fixedly secured to theproximal end of staple driver member (350). The proximal end of staplinghead assembly driver (240) is secured to a drive bracket (250) via a pin(242). It should therefore be understood that staple driver member (350)will translate longitudinally relative to outer sheath (210) in responseto translation of stapling head assembly driver (240) and drive bracket(250) relative to outer sheath (210). Stapling head assembly driver(240) is configured to flex such that stapling head assembly driver(240) may follow along the preformed curve in shaft assembly (200) asstapling head assembly driver (240) is translated longitudinallyrelative to outer sheath (210). However, stapling head assembly driver(240) has sufficient column strength to transfer distal forces fromdrive bracket (250) to staple driver member (350).

D. Exemplary Handle Assembly and User Input Features

As shown in FIG. 1, handle assembly (100) includes a casing (110) havinga lower portion that defines an obliquely oriented pistol grip (112) andan upper portion that supports a user interface feature (114) andreceives a battery pack (120), as described in greater detail below.Handle assembly (100) further includes several features that areoperable to actuate anvil (400) and stapling head assembly (300). Inparticular, handle assembly (100) includes a rotatable knob (130), asafety trigger (140) a firing trigger (150), a motor (160), and a motoractivation module (180). Knob (130) is coupled with trocar actuation rod(220) via a nut (not shown), such that coarse helical threading (224)will selectively engage a thread engagement feature within the interiorof the nut; and such that fine helical threading (226) will selectivelyengage a thread engagement feature within the interior of knob (130).These complementary structures are configured such that trocar actuationrod (220) will first translate proximally at a relatively slow rate,then translate proximally at a relatively fast rate, in response torotation of knob (130).

It should be understood that when anvil (400) is coupled with trocar(330), rotation of knob (130) will provide corresponding translation ofanvil (400) relative to stapling head assembly (300). It should also beunderstood that knob (130) may be rotated in a first angular direction(e.g., clockwise) to retract anvil (400) toward stapling head assembly(300); and in a second angular direction (e.g., counterclockwise) toadvance anvil (400) away from stapling head assembly (300). Knob (130)may thus be used to adjust a gap distance (d) between opposing surfaces(412, 322) of anvil (400) and stapling head assembly (300) until asuitable gap distance (d) has been achieved, for example as shown inFIG. 7C described below.

Firing trigger (150) is operable to activate motor (160) to therebyactuate stapling head assembly (300). Safety trigger (140) is operableto selectively block actuation of firing trigger (150) based on thelongitudinal position of anvil (400) in relation to stapling headassembly (300). Handle assembly (100) also includes components that areoperable to selectively lock out both triggers (140, 150) based on theposition of anvil (400) relative to stapling head assembly (300). Forinstance, safety trigger (140) may be blocked from rotating from anengaged position to a disengaged position until the position of anvil(400) relative to stapling head assembly (300) is within a predefinedrange. Accordingly, until the anvil position is within the predefinedrange, actuation of firing trigger (150) is blocked by safety trigger(140), thereby inhibiting firing of stapling head assembly (300).

Firing trigger (150) of the present example includes an integralactuation paddle (not shown), which may be similar to the paddledisclosed in U.S. Pub. No. 2017/0258471, incorporated by referenceabove. The paddle is configured to actuate a switch of motor activationmodule (180) (FIG. 1) when firing trigger (150) is pivoted to a firedposition. Motor activation module (180) is in communication with batterypack (120) and motor (160), such that motor activation module (180) isconfigured to provide activation of motor (160) with electrical powerfrom battery pack (120) in response to the paddle actuating the switchof motor activation module (180). Thus, motor (160) will be activatedwhen firing trigger (150) is pivoted. This activation of motor (160)will actuate stapling head assembly (300) via drive bracket (250), asdescribed in greater detail below. Though not shown, and by way ofexample only, motor (160) may be operatively coupled with drive bracket(250) via a gearbox coupled with an output shaft of motor (160), arotary cam member coupled with an output shaft of the gearbox, and a camfollower coupled with the rotary cam member, for example as disclosed inU.S. Pub. No. 2017/0258471, incorporated by reference above.

As best shown in FIGS. 1-2, handle assembly (100) is further configuredto releasably receive a battery pack (120) operable to provideelectrical power to motor (160), as noted above. It should be understoodthat battery pack (120) and handle assembly (100) may have complementaryelectrical contacts, pins and sockets, and/or other features thatprovide paths for electrical communication from battery pack (120) toelectrically powered components in handle assembly (100) when batterypack (120) is coupled with handle assembly (100). It should also beunderstood that, in some versions, battery pack (120) may be unitarilyintegrated within handle assembly (100) such that battery back (120)cannot be removed from handle assembly (100).

E. Exemplary Anastomosis Procedure with Circular Stapling Instrument

FIGS. 7A-7E show instrument (10) being used to form an anastomosis (70)between two tubular anatomical structures (20, 40). By way of exampleonly, the tubular anatomical structures (20, 40) may comprise sectionsof a patient's esophagus, sections of a patient's colon, other sectionsof the patient's digestive tract, or any other tubular anatomicalstructures. In some versions, one or more diseased portions of apatient's colon are removed, with the tubular anatomical structures (20,40) of FIGS. 7A-7E representing the remaining severed portions of thecolon.

As shown in FIG. 7A, anvil (400) is positioned in one tubular anatomicalstructure (20) and stapling head assembly (300) is positioned in anothertubular anatomical structure (40). In versions where tubular anatomicalstructures (20, 40) comprise sections of a patient's colon, staplinghead assembly (300) may be inserted via the patient's rectum. It shouldalso be understood that the procedure depicted in FIGS. 7A-7E is an opensurgical procedure, though the procedure may instead be performedlaparoscopically. Various suitable ways in which instrument (10) may beused to form an anastomosis (70) in a laparoscopic procedure will beapparent to those of ordinary skill in the art in view of the teachingsherein.

As shown in FIG. 7A, anvil (400) is positioned in tubular anatomicalstructure (20) such that shank (420) protrudes from the open severed end(22) of tubular anatomical structure (20). In the present example,purse-string suture (30) is provided about a mid-region of shank (420)to generally secure the position of anvil (400) in tubular anatomicalstructure (20). In some other variations, purse-string suture (30) istightened around the proximal end of shank (420). In some suchvariations, the proximal end of shank (420) may include a notch or otherfeature to securely capture purse-string suture (30). Continuing withthe present example, stapling head assembly (300) is positioned intubular anatomical structure (40) such that trocar (330) protrudes fromthe open severed end (42) of tubular anatomical structure (20). Apurse-string suture (50) is provided about a mid-region of shaft (332)to generally secure the position of stapling head assembly (300) intubular anatomical structure (40). Stapling head assembly (300) is thenurged distally to ensure that stapling head assembly (300) is fullyseated at the distal end of tubular anatomical structure (40).

Next, anvil (400) is secured to trocar (330) by inserting trocar (330)into bore (422) as shown in FIG. 7B. Latch members (430) engage head(334) of trocar (330), thereby providing a secure fit between anvil(400) and trocar (330). The operator then rotates knob (130) whileholding casing (110) stationary via pistol grip (112). This rotation ofknob (130) causes trocar (330) and anvil (400) to retract proximally. Asshown in FIG. 7C, this proximal retraction of trocar (330) and anvil(400) compresses the tissue of tubular anatomical structures (20, 40)between surfaces (412, 322) of anvil (400) and stapling head assembly(300). As this occurs, the operator may observe the tactile resistanceor feedback via knob (130) while turning knob (130), with such tactileresistance or feedback indicating that the tissue is being compressed.As the tissue is being compressed, the operator may visually observe theposition of an indicator needle (522) within a user interface feature(114) of handle assembly (100) to determine whether the gap distance (d)between opposing surfaces (412, 322) of anvil (400) and stapling headassembly (300) is appropriate; and make any necessary adjustments viaknob (130).

Once the operator has appropriately set the gap distance (d) via knob(130), the operator pivots safety trigger (140) toward pistol grip (112)to enable actuation of firing trigger (150). The operator then pivotsfiring trigger (150) toward pistol grip (112), thus causing paddle (158)to actuate the switch of motor activation module (180) and therebyactivate motor (160) to rotate. This rotation of motor (160) causesactuation (or “firing”) of stapling head assembly (300) by actuatingdrive bracket (250) distally to thereby drive knife member (340) andstaple driver member (350) distally, as shown in FIG. 7D. As knifemember (340) translates distally, cutting edge (342) of knife member(340) cuts excess tissue that is positioned within annular recess (418)of anvil (400) and the interior of knife member (340).

As shown in FIG. 3, anvil (400) of the present example includes abreakable washer (417) positioned within annular recess (418). Thiswasher (417) is broken by knife member (340) when the knife member (340)completes a full distal range of motion from the position shown in FIG.7C to the position shown in FIG. 7D. Features of stapler (10) may beconfigured to provide an increasing mechanical advantage as knife member(340) reaches the end of its distal movement, thereby providing greaterforce by which to break the washer (417). Of course, the breakablewasher (417) may be omitted entirely in some versions. In versions wherewasher (417) is included, it should be understood that washer (417) mayalso serve as a cutting board for knife member (340) to assist incutting of tissue.

As staple driver member (350) translates distally from the positionshown in FIG. 7C to the position shown in FIG. 7D, staple driver member(350) drives staples (90) through the tissue of tubular anatomicalstructures (20, 40) and into staple forming pockets (414) of anvil(400). Staple forming pockets (414) deform the driven staples (90) intoa “B” shape or a three-dimensional shape, for example, such that theformed staples (90) secure the ends of tissue together, thereby couplingtubular anatomical structure (20) with tubular anatomical structure(40).

After the operator has actuated stapling head assembly (300) as shown inFIG. 7D, the operator rotates knob (130) to drive anvil (400) distallyaway from stapling head assembly (300), increasing the gap distance (d)to facilitate release of the tissue between surfaces (412, 322). Theoperator then removes instrument (10) from the patient, with anvil (400)still secured to trocar (330). Referring back to the example where thetubular anatomical structures (20, 40) comprise sections of a patient'scolon, instrument (10) may be removed via the patient's rectum. Withinstrument (10) removed, the tubular anatomical structures (20, 40) areleft secured together by two annular arrays of staples (90) at ananastomosis (70) as shown in FIG. 7E. The inner diameter of theanastomosis (70) is defined by the severed edge (60) left by knifemember (340).

F. Exemplary User Interface Feature of Handle Assembly

As shown best in FIG. 8, handle assembly (100) of surgical staplinginstrument (10) further includes a user interface feature (114)configured to provide the operator with visual feedback indicating thepositioning of anvil (400) in relation to stapling head assembly (300)during a surgical procedure. The operator may thus observe userinterface feature (114) while rotating knob (130) to confirm whether asuitable gap distance (d) between anvil (400) and stapling assembly(300) has been achieved.

User interface feature (114) of the present example includes a graphicalindicator (500), which includes fixed linear indicia (502, 504, 506),graphical representations (510, 512) of staples, and a checkmark graphic(514). User interface feature (114) further defines a window (520)through which an indicator needle (522) may be viewed. In somevariations, user interface feature (114) further includes a field (530)that may indicate a diameter associated with the size of stapling headassembly (300), the size of staples in stapling head assembly (300), thesize of the gap defined between anvil (400) and stapling head assembly(300), and/or other information. By way of example only, field (530) mayindicate a stapling head assembly (300) size of 23 mm, 25 mm, 29 mm, or31 mm.

As the operator rotates knob (130) to adjust the longitudinal positionof anvil (400) relative to stapling head assembly (300), the operatormay observe the position of indicator needle (522) through window (520).Initially, indicator needle (522) may be positioned at or near thedistal end of window (520). As anvil (400) continues to move proximally,indicator needle (522) will eventually move proximally relative towindow (520). The operator may view the position of indicator needle(522) in relation to fixed linear indicia (502, 504, 506). Thedistal-most and proximal-most indicia (502, 506) may represent theboundaries of a “green zone,” which is the acceptable range of distancebetween anvil (400) and stapling head assembly (300) for successfulactuation of stapling head assembly (300). Thus, if indicator needle(522) is distal to distal-most indicia (502), the distance between anvil(400) and stapling head assembly (300) is too large; and if indicatorneedle (522) is proximal to proximal-most indicia (506), the distancebetween anvil (400) and stapling head assembly (300) is too small.Indicia (504) is longitudinally positioned between indicia (502, 506).Graphical representation (510) represents a relatively tall formedstaple (e.g., suitable for use in relatively thick tissue); whilegraphical representation (512) represents a relatively short formedstaple (e.g., suitable for use in relatively thin tissue). Graphicalrepresentations (510, 512) may thus facilitate the operator's decision,based on tissue observations or otherwise, on whether and how to achievea desired formed staple height by selecting an appropriate correspondingspatial relationship between indicator needle (522) and indicia (502,504, 506).

In the present example, window (520) is illuminated via a light emittingdiode (LED) (not shown), further facilitating viewing of indicatorneedle (522) in window (520). In addition, checkmark graphic (514) isilluminated via another LED (not shown) when stapling head assembly(300) completes a stapling and cutting cycle. Thus, the operator mayfurther rely on illumination of checkmark graphic (514) to confirm thatthe stapling and cutting cycle is complete, to thereby verify that it issafe to advance anvil (400) distally away from the anastomosis (70) torelease the tissue and thereafter remove instrument (10) from thepatient.

Circular surgical stapling instrument (10) may be further configured andoperable in accordance with at least some of the teachings of U.S. Pub.No. 2017/0258471, incorporated by reference above.

II. Exemplary Circular Surgical Stapling Instrument Having IndependentlyControlled Closure, Stapling, and Cutting

In some instances, it may be desirable to provide a version of circularsurgical stapling instrument (10) that exhibits powered actuation ofanvil (400) in addition to powered actuation of internal firingcomponents of stapling head assembly (300). Furthermore, it may bedesirable to provide such a version of instrument (10) with a pluralityof actuators that enable independent, powered actuation of anvil (400),staple driver member (350), and knife member (340), such that theresulting closure, stapling, and cutting strokes performed by such aninstrument may be controlled independently from one another in responseto user input.

While the teachings below are disclosed in the context of circularsurgical staplers, it will be appreciated that such teachings may beapplied to other types of surgical staplers as well. By way of exampleonly, such other staplers may include right-angle surgical staplers ofthe type disclosed in U.S. Pat. No. 10,045,780, entitled “Method ofApplying Staples in Lower Anterior Bowel Resection,” issued Aug. 14,2018, the disclosure of which is incorporated by reference herein.

A. Overview of Circular Surgical Stapling Instrument HavingIndependently Controlled Actuators

FIG. 9 shows an exemplary circular surgical stapling instrument (600)that exhibits a configuration and functionality of the kind describedabove. It will be understood that instrument (600) is similar toinstrument (10) described above except as otherwise described below.Similar to instrument (10), instrument (600) generally includes a bodyassembly in the form of a handle assembly (610), a shaft assembly (630)extending distally from handle assembly (610), a stapling head assembly(640) disposed at a distal end of shaft assembly (630), and an anvil(650) configured to releasably couple with an actuatable closure memberin the form of a trocar (642). Anvil (650) is selectively retractableand extendable by trocar (642) relative to stapling head assembly (640)for clamping tissue against a distally facing deck surface (644)thereof. Stapling head assembly (640) is selectively operable to ejectstaples distally into the clamped tissue and against anvil (650), and tocut the clamped tissue with a cylindraceous knife member (not shown)similar to knife member (340) described above. Accordingly, staplinghead assembly (640) and anvil (650) cooperate to define an end effectorstapling assembly operable to clamp, staple, and cut tissue in responseto user inputs.

Handle assembly (610) includes a casing (612) defining a pistol grip(614), a user interface (616) disposed on an upper side of casing (612)adjacent to a distal end of casing (612), and a knob (618) rotatablydisposed at a proximal end of casing (612). User interface (616) andknob (618) are similar to user interface (114) and knob (130) describedabove except as otherwise described below. Casing (612) of the presentexample includes an open-ended proximal cavity (not shown) configured toreleasably receive and retain a battery pack (620) similar to batterypack (120) and operable to power a motor unit (660) (see FIG. 10) housedwithin casing (612).

Handle assembly (610) of the present example further includes a safetymember (622), a closure trigger (624), and a firing trigger (626) eachmovable independently relative to pistol grip (614). Actuation ofclosure trigger (624) is configured to activate motor unit (660) toinitiate actuation of a trocar actuator (662) (see FIG. 10) and therebyeffect closure of anvil (650) relative to stapling head assembly (640)to clamp tissue therebetween. Actuation of firing trigger (626) isconfigured to activate motor unit (660) to initiate actuation of astaple actuator (664) and a knife actuator (666) (see FIG. 10) tothereby staple and cut the clamped tissue. As described in greaterdetail below in connection with FIG. 11, instrument (600) is configuredto control actuation of staple actuator (664) and knife actuator (666)independently in response to a single actuation of firing trigger (626).In this manner, a precise timing of the cutting stroke initiationrelative to the stapling stroke initiation may be achieved.

Safety member (622) of the present example is in the form of aprojection, such as a pivotable trigger similar to safety trigger (140),and is configured to directly or indirectly engage closure trigger (624)and/or firing trigger (626) to selectively block actuation thereof. Forinstance, safety member (622) may be configured to block actuation ofclosure trigger (624) until instrument (600) detects that anvil (650)has been fully attached to trocar (642). Additionally, or in thealternative, safety member (622) may be configured to block actuation offiring trigger (626) until anvil (650) has assumed a predeterminedlongitudinal position relative to stapling head assembly (640) thatdefines a particular gap distance (d) therebetween (see FIG. 7C).

Actuators (662, 664, 666) of instrument (600), shown schematically inFIG. 10, are configured to operatively couple corresponding actuatablecomponents of instrument (600) with motor unit (660). In particular,trocar actuator (662) operatively couples a trocar (642) with motor unit(660). Accordingly, trocar actuator (662) is configured to actuatetrocar (642) and thus anvil (650) proximally and distally in response toactivation of motor unit (660) when motor unit (660) is operativelyengaged with trocar actuator (662). Trocar actuator (662) may include anelongate member similar to trocar actuation rod (220) combined withtrocar actuation band assembly (230) of instrument (10), which istranslatably disposed within shaft assembly (630).

Staple actuator (664) operatively couples a staple driver member (notshown) of stapling head assembly (640) with motor unit (660)independently of trocar actuator (662). Accordingly, staple actuator(664) is configured to actuate the staple driver member, and thusstaples (not shown) housed within stapling head assembly (640), distallyin response to activation of motor unit (660) when motor unit (660) isoperatively engaged with staple actuator (664). Staple actuator (664)may include an elongate member similar to stapling head assembly driver(240) of instrument (10), which is translatably disposed within shaftassembly (630) independently of trocar actuator (662).

Knife actuator (666) operatively couples a cylindraceous knife member(not shown) of stapling head assembly (640) with motor unit (660)independently of trocar actuator (662) and staple actuator (664).Accordingly, knife actuator (666) is configured to actuate the knifemember longitudinally in response to activation of motor unit (660) whenmotor unit (660) is operatively engaged with knife actuator (666). Knifeactuator (666) may include an elongate member similar to stapling headassembly driver (240) of instrument (10), which is translatably disposedwithin shaft assembly (630) independently of trocar actuator (662) andstaple actuator (664). In this manner, actuators (662, 664, 666) areconfigured to cooperate with motor unit (660) to provide independentlyactuated clamping of tissue, stapling of the tissue, and cutting of thetissue.

Knob (618) of handle assembly (610) of the present example isoperatively coupled with trocar actuator (662) such that knob (618) isoperable as an anvil closure bailout feature. In that regard, trocaractuator (662) is driven primarily by motor unit (660) but is alsotranslatable longitudinally in response to rotation of knob (618), forexample when motor unit (660) is deactivated or otherwise disengagedfrom trocar actuator (662). Accordingly, knob (618) may be rotatedfollowing partial or full proximal retraction of anvil (650) towardstapling head assembly (640) to thereby extend anvil (650) distally awayfrom stapling head assembly (640), for example to release tissuecaptured therebetween. In such versions, knob (618) may be coupled withtrocar actuator (662) via features similar to those described above inconnection with knob (130) of instrument (10), including threadedportions (224, 226) of trocar actuation rod (220), for example. It willbe understood, however, that knob (618) may be omitted from instrument(600) in some versions such that trocar actuator (662) is driven solelyby motor unit (660).

Instrument (600) may be further configured and operable in accordancewith at least some of the teachings of U.S. Pat. No. 9,445,816, entitled“Circular Stapler with Selectable Motorized and Manual Control,” issuedSep. 20, 2016; U.S. Pat. No. 9,532,783, entitled “Circular Stapler withSelect Motorized and Manual Control, Including a Control Ring,” issuedJan. 3, 2017; U.S. Pat. No. 9,597,081, entitled “Motor Driven RotaryInput Circular Stapler with Modular End Effector,” issued Mar. 21, 2017;U.S. Pat. No. 9,463,022, entitled “Motor Driven Rotary Input CircularStapler with Lockable Flexible Shaft,” issued Oct. 11, 2016; U.S. Pub.No. 2018/0368836, entitled “Surgical Stapler with Independently ActuatedDrivers to Provide Varying Staple Heights,” published Dec. 27, 2018;and/or any of the other patent references identified herein, thedisclosures of which are incorporated by reference herein.

B. Exemplary Control System of Circular Surgical Stapling Instrument

As shown schematically in FIG. 10, instrument (600) further includes acontrol system (670) operable to control actuation of trocar actuator(662), staple actuator (664), and knife actuator (666) of instrument(600). Control system (670) includes a control module (672), motor unit(660), user interface (616), and a sensor (674) suitably arranged suchthat control module (672) communicates with each of motor unit (660),user interface (616), and sensor (674). Control module (672) includes aprocessor and is operable to store pre-programmed instrument controlalgorithms and receive input from user interface (616) and sensor (674).Based on these stored control algorithms and received input, controlmodule (672) is configured to control motor unit (660) with pulse-widthmodulation (PWM) to drive actuation of trocar actuator (662), stapleactuator (664), and knife actuator (666) independently from one anotherfor clamping, stapling, and cutting tissue.

Motor unit (660) includes one or more motors and is operatively coupledwith trocar actuator (662), staple actuator (664), and knife actuator(666). In some versions, motor unit (660) may comprise a single motoroperatively coupled with and configured to drive all three actuators(662, 664, 666). In such versions, motor unit (660) may be coupled withactuators (662, 664, 666) via one or more power transmission assemblies(not shown), such as a gear assembly, various suitable types of whichwill be apparent to those of ordinary skill in the art in view of theteachings herein and in the incorporated references. In other versions,motor unit (660) may comprise three motors, each being dedicated todrive a respective one of actuators (662, 664, 666). In furtherversions, motor unit (660) may comprise two motors, a first motor ofwhich is configured to drive trocar actuator (662) and a second motor ofwhich is configured to drive staple actuator (664) and knife actuator(666) with assistance of a power transmission assembly. It will beunderstood that motor unit (660) may comprise various other quantitiesand arrangements of motors in other versions.

Sensor (674) is arranged within or otherwise coupled to stapling headassembly (640), shaft assembly (630), or handle assembly (610), and isoperable to monitor one or more conditions of instrument (600) duringuse. For instance, sensor (674) may be configured to monitor translationof any one or more of actuators (662, 664, 666) and/or their adjoiningcomponents, such as trocar (642). In some such versions, sensor (674)may be mounted directly to any one of actuators (662, 664, 666) or anadjoining component thereof. In other such versions, sensor (674) may befixedly mounted within stapling head assembly (640), shaft assembly(630), or handle assembly (610), such that actuators (662, 664, 666) andtheir adjoining components move relative to sensor (674).

In some versions, sensor (674) may be configured to detect secureattachment of anvil (650) to trocar (642), for example as disclosed inU.S. Pat. No. 10,307,157, incorporated by reference above; or in U.S.Pat. App. No. [Atty. Ref. END9142USNP1], entitled “Anvil Retention andRelease Features for Powered Circular Surgical Stapler,” filed on evendate herewith, the disclosure of which is incorporated by referenceherein. In other versions, sensor (674) may be configured to detectcertain characteristics of the particular stapling head assembly (640)coupled with shaft assembly (630), such as a diameter of stapling headassembly (640) or a size of the staples (not shown) housed therein. Insome such versions, sensor (674) may be configured to detect suchcharacteristics of stapling head assembly (640) via radio-frequencyidentification (RFID) of electronic information stored within a tagelement disposed on or within stapling head assembly (640), for exampleas disclosed in U.S. Provisional Pat. App. No. 62/868,457, entitled“Surgical Systems with Multiple RFID Tags,” filed on Jun. 28, 2019, thedisclosure of which is incorporated by reference herein.

Still in other versions, sensor (674) may be in direct communicationwith motor unit (660). For instance, sensor (674) may comprise a currentsensor operable to monitor an electrical current drawn by motor unit(660), or an encoder operable to monitor a rotational output of motorunit (660). Moreover, while only one sensor (674) is illustrated in thediagram of FIG. 10, it will be understood that sensor (674) may comprisea plurality of sensors, where each individual sensor (674) is configuredto monitor and communicate with control module (672) regarding arespective one or more conditions of instrument (600). Furthermore, itwill be understood that sensor (674) may be in the form of a sensorassembly that includes various suitable types of sensors readilyapparent to those of ordinary skill in the art in view of the teachingsherein and not otherwise described herein.

User interface (616) is similar to user interface (114) described above,except that user interface (616) is further configured to receive andcommunicate user input to control module (672). In that regard, userinterface (616) may include one or more buttons, dials, other actuatableelements, or displayed graphics that are selectable by a user toindicate certain information pertaining to a surgical procedure to beperformed or to stapling head assembly (640). By way of example only,such information may include any of the following: a desired stapleformation height; a corresponding gap between anvil (650) and stapling7head assembly (640) to which anvil (650) should be actuated duringclosure; a type or nominal thickness of tissue being fired upon withinstrument (600); and/or a diameter of stapling head assembly (640).Such information, in combination with information provided by sensor(674), may be used by control module (672) to adjust strokes and/orrates of actuation of actuators (662, 664, 666), and/or to adjust timingpauses between the powered actuations of actuators (662, 664, 666) toensure optimal clamping, stapling, and cutting of tissue during aprocedure, for example as described in greater detail below.

C. Exemplary Method for Controlling Circular Surgical Stapler

FIG. 11 shows an exemplary method (700) for controlling circularsurgical stapling instrument (600) via control system (670) shown inFIG. 10. At step (702), instrument (600) powers on in response to beingenergized by battery pack (620), for example when battery pack (620) isfully inserted into the proximal end of handle assembly (610) afterinstrument (600) is removed from product packaging. Upon removal fromthe packaging, anvil (650) is already secured to trocar (642) and is ina fully open state, and a staple retainer (not shown) is secured to decksurface (644).

After instrument (600) powers on in the present example, control module(672) enters an anvil stroke calibration mode at step (704), which mayoccur automatically or in response to a user input, for example providedvia user interface (616). In this calibration mode, control module (672)activates motor unit (660) to drive trocar actuator (662) to retracttrocar (642) proximally and thereby close anvil (650) against the stapleretainer, or alternatively against deck surface (644) in the event thatthe staple retainer has been removed. Control module (672) may detectthat anvil (650) has reached a closed position by detecting via sensor(674) an increase in the electrical current load of motor unit (660)upon contact of anvil (650) with the staple retainer or deck surface(644). Control module (672) observes the stroke (i.e., longitudinaldisplacement) of anvil (650) during this retraction process and comparesit to an expected stroke of anvil (650). Based on this comparison andany differences observed between the two stroke values, control module(672) then calibrates an actuation algorithm that is executed toactivate motor unit (660) to actuate trocar actuator (662), and therebyensure precise actuations of anvil (650) thereafter during a surgicalprocedure. In addition, or in the alternative, calibration of the anvilstroke may be performed by control module (672) in real time during asurgical procedure when anvil (650) is being retracted to clamp tissue.Such calibration of the anvil stroke is described in further detailbelow. It will be understood that the strokes of one or more otheractuatable members of instrument (600) may be calibrated in a similarmanner before or during a surgical procedure, and also that thecalibration of the anvil closure stroke may be applied by control module(672) to also calibrate the stapling stroke and/or the cutting stroke ofinstrument (600).

At step (706), control module (672) determines a diameter of staplinghead assembly (640). As described above, stapling head assembly (640)may be releasably attached to shaft assembly (630) such that staplinghead assemblies (640) of various diameters may be interchangeablycoupled with the distal end of shaft assembly (630) depending on a lumensize of the tissue structure being operated on with instrument (600).Control module (672) is configured to make this size determination basedon user input provided via user interface (616) and/or informationprovided by sensor (674), for instance when sensor (674) is configuredto detect the size of stapling head assembly (640) in the mannerdescribed above.

At step (708), control module (672) receives from user interface (616)input that indicates a desired height of staples to be formed in tissue,as selected by the operator via user interface (616). Control module(672) equates this staple height to a corresponding gap distance (d)(see FIG. 7C) to be established between anvil (650) and deck surface(644) of stapling head assembly (640) at a closed position of anvil(650), in order to achieve the selected staple height.

While steps (704, 706, 708) are shown in FIG. 11 as being performed in aparticular order, it will be appreciated that these steps (704, 706,708) may be performed in a variety of orders relative to one anotherfollowing the powering on of instrument (600) in step (702) and beforethe actuation of staple actuator (664) described below.

Following completion of steps (704, 706, 708), the operator detachesanvil (650) from trocar (642) and proceeds to position anvil (650)within a first tubular tissue structure of a patient and separatelyposition stapling head assembly (640) within a second tubular tissuestructure of the patient. The operator then attaches anvil (650) totrocar (642) within the patient, for example as shown in FIGS. 7A-7Bdescribed above, at which point control module (672) detects at step(710) that the attachment has been made. Such detection may be made bysensor (674), which communicates a corresponding signal to controlmodule (672).

At step (712), control module (672) detects that closure trigger (624)has been actuated by the operator. Control module (672) then proceeds tostep (714) and directs motor unit (660) to drive trocar actuator (662)to actuate trocar (642) proximally and thereby retract anvil (650) to aclosed position at which the selected staple height and correspondinggap distance (d) are achieved. In some versions, control module (672)may be configured to initiate retraction of trocar (642) and anvil (650)only in response to an actuation of closure trigger (624) that occursafter attachment of anvil (650) to trocar (642) has been detected atstep (710). The operator may monitor the retraction of anvil (650)toward its closed position via visual indicia and/or displayed graphicsof user interface (616).

Additionally, in some versions, control module (672) may control motorunit (660) to retract anvil (650) proximally through the anvil closurestroke in two sequential stages. For instance, control module (672) maydirect motor unit (660) to retract anvil (650) through a first portionof the anvil closure stroke, at which point control module (672) pausesactivation of motor unit (660) for a predetermined period of time (e.g.,several seconds). At the end of this wait period, control module (672)reactivates motor unit (660) to continue retracting anvil (650) throughthe remaining portion of the anvil closure stroke to its closedposition. Inclusion of such a pause in the retraction of anvil (650) mayenable the tissue being compressed between anvil (650) and deck surface(644) to at least partially settle (or “creep”). Advantageously, thissettling of tissue yields a reduction of the axial extension load ontrocar (642) and the resulting electrical current load of motor unit(660) as anvil (650) advances proximally to its fully closed positiondefined by the target staple height input provided by the user in step(708).

At step (716), control module (672) detects that firing trigger (626)has been actuated by the operator following completion of the anvilclosure stroke. In the present example, in response to detecting thisactuation, control module (672) observes completion of a predeterminedperiod of time measured from completion of the anvil closure stroke,during which staple actuator (664) and knife actuator (666) remainstationary. This wait period after anvil closure enables the clampedtissue to settle (or “creep”) into its fully compressed state beforestapling head assembly (640) is fired, thus reducing the axial forces onstaple actuator (664) and knife actuator (666), and the resultingcurrent loads of motor unit (660), during the respective stapling andcutting sequences. It will be understood that this wait period may beomitted in some versions.

Upon completion of the wait period denoted in step (718), control module(672) initiates distal actuation of the staple driver member (not shown)at step (720) to begin stapling the clamped tissue. In particular,control module (672) activates motor unit (660) to engage and drivestaple actuator (664) to actuate the staple driver member distallythrough stapling head assembly (640) and thereby drive staples intotissue and against anvil (650), for example similar to the manner shownin FIG. 7D. Upon initiating actuation of staple actuator (664), controlmodule (672) at step (722) observes another predetermined period of timeduring which motor unit (660) continues to drive staple actuator (664)through the stapling stroke. Simultaneously, at step (724) controlmodule (672) communicates with sensor (674) to detect when the stapledriver member reaches a predetermined longitudinal position withinstapling head assembly (640). Such a position may correspond to thepoint at which individual staple drivers (not shown), similar to stapledrivers (352) described above, reach deck surface (644) such that thestaples are at least partially formed within the clamped tissue. Thisprocess is described in further detail below in connection with FIGS.17-19, and in U.S. Pat. App. No. [Atty. Ref. END9129USNP1], entitled“Method for Controlling Cutting Member Actuation for Powered SurgicalStapler,” filed on even date herewith, the disclosure of which isincorporated by reference herein.

In response to detecting completion of the predetermined time period ofstep (722) and/or detecting at step (724) that the staple driver memberhas reached the predetermined longitudinal position, control module(672) then initiates distal actuation of the knife member (not shown) atstep (726) to begin cutting the tissue. In particular, control module(672) activates motor unit (660) to engage and drive knife actuator(666) to actuate the knife member distally through stapling headassembly (640) and thereby cut the tissue, for example similar to themanner shown in FIG. 7D.

As noted above, delaying initiation of the cutting stroke relative toinitiation of the stapling stroke, as enabled by independent actuationof staple and knife actuators (662, 664, 666), ensures at least partialformation of staples within the tissue before tissue cutting commences.Advantageously, this approach enables the staples to anchor within theclamped tissue before cutting, and thereby prevent lateral shifting ofthe tissue and resulting malformation of the staples when the knifemember is driven distally.

The end of the distal cutting stroke of the knife member may correspondto a point at which the knife member breaks a washer (not shown) withinanvil (650) similar to washer (417) described above. Upon completion ofthe distal cutting stroke, control module (672) at step (728) directsmotor unit (660) to retract the knife member proximally back intostapling head assembly (640). In some versions, knife member distalextension and subsequent proximal retraction may be achieved by poweringmotor unit (660) through a continuous, uniform range of motion, forexample as disclosed in U.S. Pub. No. 2017/0258471 incorporated byreference above. In other versions, control module (672) may beprogrammed to communicate with sensor (674) to detect completion of thedistal cutting stroke, and thereafter specifically direct motor unit(660) to drive knife actuator (666) in an alternative manner to retractthe knife member proximally. In any of such versions, sensor (674) maycomprise an encoder configured to monitor a rotational output of motorunit (660).

Simultaneously with or subsequently to knife retraction step (728),control module (672) at step (730) directs motor unit (660) to drivetrocar actuator (662) distally to thereby extend anvil (650) distally toa predetermined position relative to deck surface (644) of stapling headassembly (640). This distal extension enables the stapled tissue to bereleased from between anvil (650) and stapling head assembly (640) sothat instrument (600) may be withdrawn from the patient while anvil(650) remains attached to trocar (642).

III. Exemplary Method for Calibrating Closure Rate and/or Closure Stroke

As described above, it may be desirable to refine the longitudinalactuation (“closure stroke”) and/or rate of actuation (“closure rate”)of longitudinal actuation of a movable member for improved clamping.Proper calibration of this closure stroke and/or closure rate enablescircular stapler (600) to more precisely clamp patient tissue. As willbe described in greater detail below, tissue compression may by improvedby monitoring initial tissue contact, gap, and/or force to control theclosure rate and/or the closure stroke.

Control module (672) of the present example is configured to store andexecute a movable member actuation algorithm (e.g. including closurestroke and closure rate) to longitudinally actuate trocar actuator (662)(and thus trocar (642) and anvil (650)) to clamp tissue. It may bedesirable to calibrate trocar actuator (662), staple actuator (664), andknife actuator (666) before or during a surgical procedure. Controlmodule (672) of the present example is configured to store and execute astaple driver member actuation algorithm to longitudinally actuatestaple actuator (664) (and thus staple driver member) to staple tissue.Control module (672) of the present example is configured to store andexecute a knife member actuation algorithm to longitudinally actuateknife actuator (666) (and thus knife member) to cut tissue. Each ofthese actuation algorithms stored by control module (672) includes acorrelation between a given rotational output of motor unit (660) and anexpected longitudinal displacement of the corresponding actuated memberof instrument (600) effected by that particular rotational output. Asdescribed above, the rotational output of motor unit (660) may bemonitored by an encoder operatively coupled with motor unit (660) and incommunication with control module (672). As described below, thelongitudinal strokes of actuators (662, 664, 666) may be calibrated byadjusting the corresponding actuation algorithms stored by controlmodule (672).

A. First Exemplary Method to Adjust Closure Rate and/or Closure Stroke

An exemplary method (800) of operating a powered surgical stapler, suchas circular surgical stapling instrument (600), is shown and describedwith reference to FIG. 12. Particularly, FIG. 12 shows a diagrammaticview of method (800) for calibrating the closure rate and/or closurestroke of the movable member (e.g. trocar (642), anvil (650), or trocaractuator (662)) of instrument (600) of FIG. 9 by adjusting actuationalgorithms executed by control system (670) of FIG. 10. As previouslydescribed with reference to FIG. 9, instrument (600) includes motor unit(660), shaft assembly (630) operatively coupled with motor unit (660), acontroller (e.g. control module (672)) in communication with motor unit(660), and sensor assembly (674) in communication with control module(672), anvil (650), and deck surface (644) that opposed anvil (650). Themovable member (e.g. trocar (642), and anvil (650), or trocar actuator(662) shown in FIG. 13) is actuatable between an open position and aclosed position. In the open position (similar to FIG. 7C withreferencing instrument (10)), trocar (642) is configured to receive atleast first and second tissue layers (T1, T2) between deck surface (644)and anvil (650). In the closed position (similar to FIG. 7D referencinginstrument (10)), anvil (650) and deck surface (644) compress at leastfirst and second tissue layers (T1, T2) together.

As shown in FIG. 12, method (800) begins at step (802) with aninitiating event, which may be an actuation of closure trigger (624)following attachment of anvil (650) to trocar (650) during the surgicalprocedure. In response to the initiating event, control module (672)executes the stored movable member actuation algorithm at step (804) toactivate motor unit (660) to actuate trocar actuator (662) proximally totransition anvil (650) from the open position towards the closedposition. Prior to or during execution of the movable member actuationalgorithm, control module (672) determines that a monitored one oftrocar (642), anvil (650), or trocar actuator (662) is in apredetermined position, e.g. via detection by sensor assembly (674)using position sensor (680). By way of example only, the predeterminedposition may correspond to anvil (650) in a fully open position.

At step (806), method (800) includes sensing closure data at a firsttime using sensor assembly (674) as the movable member (trocar (642),anvil (650), or trocar actuator (662)) moves from the open positiontowards the closed position. The closure data may include one or more ofan initial tissue contact position (see FIG. 13), a gap (δ_(QC), δ_(FC),δ_(AT)) disposed between anvil (650) and opposing deck surface (644), oran axial force (F_(A)) on anvil (650). As shown in FIG. 13, the initialtissue contact position is defined as the position when first and secondtissue layers (T1, T2) are fully approximated but not yet compressedtogether. In the initial tissue contact position, an initial tissuecontact gap (δ_(FC)) is defined between deck surface (644) or anvil(650). With further reference to FIGS. 13 and 14, gap (δ_(QC), δ_(FC),δ_(AT)) shrinks as movable member moves from the open position towardsthe closed position. Similar to step (806) described above, method (800)also includes step (808) sensing closure data at a second time, afterthe first time, using sensor assembly (674) as movable member moves fromthe open position towards the closed position.

FIG. 13 shows a schematic side cross-sectional view of trocar (642) andanvil (650) of circular surgical stapling instrument (600) of FIG. 9operatively coupled with control system (670) of FIG. 10, where firstand second tissue layers (T1, T2) are disposed between trocar (642) anddeck surface (644). As shown in FIG. 13, sensor assembly (674) mayinclude one or more of a current sensor (676), a force sensor (678), orposition sensor (680), which may be operatively coupled with motor unit(660). Sensor assembly (674) is in communication with control module(672) which is in communication with motor unit (660) to affect trocaractuator (662). Control module (672) may determine present longitudinaldisplacement of anvil (650) relative to deck surface (644) based on asignal provided by position sensor (680). As shown in FIG. 13, positionsensor (680) may include first and second sensor portions (682, 684),where first sensor portion (682) is disposed on a proximally facingsurface (686) of anvil (650) and second first sensor portion (684) isdisposed on deck surface (644). As shown, proximally facing surface(686) is disposed opposite deck surface (644) and separated by gap(δ_(QC), δ_(FC), δ_(AT))

This increase in axial force (F_(A)) may be detected by one or moresensors of sensor assembly (674) in the form of current sensor (676) orforce sensor (678) that communicate with control module (672) as shownin FIG. 13. For example, control module (672) may determine that axialforce (F_(A)) on anvil (650) has changed based on the closure dataprovided by force sensor (678) that indicates an increase in axial force(F_(A)) exerted on trocar actuator (662) (and thus also anvil (650) andtrocar (642)). Similarly, this axial force (F_(A)) may be exerted ontrocar actuator (662) (and thus also anvil (650) and trocar (642)), ormay be an electrical current drawn by motor unit (660) while actuatingtrocar actuator (662). The axial force (F_(A)) on anvil (650) isproportional to the electrical current drawn by motor unit (660) inmoving from the open position to the closed position. It will beunderstood that the closure of anvil (650) against a structure induces alongitudinal extension force in anvil (650), trocar (642), and trocaractuator (662) that makes further proximal retraction of these closurecomponents by motor unit (660) more difficult, thus increasing theelectrical current force of motor unit (660). As a result, controlmodule (672) may determine that axial force (F_(A)) on anvil (650) hasincreased based on the closure data provided by current sensor (676)that indicates an increase in electrical current drawn by motor unit(660).

FIG. 14 shows a line graph (900) of an exemplary closure of trocaractuator (662) (and thus trocar (642) and anvil (650)) according tomethod (800) described above. For the closure displacement curve (DC),the X-axis of graph (900) represents time and the Y-axis of graph (900)represents an anvil closure gap (δ), as interpreted by control module(672). For the displacement curve (DC), a predetermined gap may be aquick close gap (δ_(QC)) that has a higher first closure velocity (CV₁)than at first tissue closure gap (δ_(FC)) as shown by second closurevelocity (CV₂). Closure velocities (CV₁, CV₂, CV₃, CV₄) are measured asthe change (i.e. slope) of displacement curve (DC). As shown in FIG. 14,gap (δ_(QC), δ_(FC), δ_(AT)) formed between anvil (650) and opposingdeck surface (644) decreases as movable member (trocar (642), anvil(650), trocar actuator (662)) moves from the open position towards theclosed position (shown by gap (δ_(AT1))).

For the closure force curve (FC), the X-axis of graph (900) representstime and the Y-axis of graph (900) represents an anvil force (F_(A)), asinterpreted by control module (672). The closure displacement curve (DC)and the closure force curve (FC) are superimposed on top of each otherto show the relevant relationships at various times, such as at aninitial time (t₀), a quick close time (t_(QC)), a partially closed time(t_(AT)), and a fully closed time (t_(AT1)). As shown, axial force(F_(A)) on anvil (650) increases once tissue is contacted. There is nota significant force (F_(A)) exerted on anvil (650) in the quick closeregion as first and second tissue layers (T1, T2) are not being activelycompressed together. The increase in the closure force curve (FC)between quick close time (t_(QC)) and initial tissue contact time(t_(FC)) is caused by first and second tissue layers (T1, T2) beingfully approximated. The axial force (F_(A)) on anvil (650) peaks at nearfully closed time (t_(AT1)), and then decreases thereafter.

At step (810), method (800) also includes communicating closure data ofsensor assembly (674) to control module (672). At step (812), controlmodule (672) compares the current longitudinal displacement of themonitored movable member observed by control module (672), via sensorassembly (674), to the closure rate and closure stroke stored by controlmodule (672). Control module (672) determines at step (812) whetherthere is a difference between the present closure rate and closurestroke and the closure rate and closure stroke obtained using theclosure data. If the values are equal or within a predeterminedacceptable range of one another such that there is no significantdifference, control module (672) proceeds to step (814) to continues toexecute the current algorithm in response to user actuations of closuretrigger (624) and firing trigger (626), for example as outlined above inthe steps of method (700).

Alternatively, if control module (672) determines that there is asignificant difference between the values, control module (672) proceedsto step (816) to adjust the closure rate to an adjusted closure rate andthe closure stroke to an adjusted closure stroke based on the determineddifference. The adjusted closure rate is the speed at which the gapbetween anvil (650) and opposing deck surface (644) shrinks movingtoward the closed position. The adjusted closure stroke is longitudinaldistance between anvil (650) and opposing deck surface (644) between theopen and closed positions. Adjusting the closure rate and or closurestroke may improve compression of first and second tissue layers (T1,T2) relative to a user selected staple size.

At step (818), method (800) also includes controlling motor unit (660)by executing at least one of the adjusted closure rate or the adjustedclosure stroke based on determination of control module (672).Alternatively, control unit (672) may control motor unit (660) usingeach of the adjusted closure rate and the adjusted closure stroke basedon the determination of control module (672). At step (820), method(800) includes determining with control module (672) whether the movablemember has reached the closed position. If yes, method (800) may move tostep (822) where the algorithm may be terminated once the closedposition is reached with using the adjusted closure rate and/or adjustedclosure stroke. If no, method (800) may loop back to sense closure dataat additional times as discussed above with reference to steps (806,808), such that method (800) continues.

The combined sensing of first tissue contact position, gap demonstratinganvil position, and axial force (F_(A)) improves closure rate and/orclosure stroke in instrument (600) to reduce collateral damage andimprove compression relative to the user's selection of staple size,thereby improving the anastomosis. Additionally, sensing the firsttissue contact position, anvil position tissue gap, and axial force(F_(A)) as a means for adjusting the closure rate and/or the closurestroke may increase reliability, minimize collateral damage, and improvehemostasis.

B. Adjusting Stapling and/or Knife Algorithms Based on Closure Rateand/or Closure Stroke

In addition to controlling the longitudinal displacement of trocaractuator (662) during the anvil closure stroke, control module (672) maycontrol the longitudinal displacement of staple actuator (664) duringthe stapling stroke and the longitudinal displacement of knife actuator(666) during the cutting stroke based on the tissue gap user input. Inparticular, control module (672) may tailor the longitudinaldisplacements of each actuator (662, 664, 666) to ensure that actuators(662, 664, 666) are actuated longitudinally by the appropriate amount toprovide a full stapling member actuation stroke and a full knife memberactuation stroke without under-actuation or over-actuation relative tothe target tissue gap.

In that regard, it will be appreciated that calibration of thelongitudinal strokes of staple actuator (664) and knife actuator (666)may be desirable to ensure that staple actuator (664) and knife actuator(666) are actuated by the appropriate amount during a surgicalprocedure. Moreover, it may be beneficial to use the closure dataobtained during the movable member actuation algorithm to affect thestaple member actuation algorithm and the knife member actuationalgorithm. As such, the corresponding staple member actuation algorithmand knife member actuation algorithm may be adjusted appropriately basedon the adjustments made to the movable member actuation algorithm viamethod (800). Alternatively, the staple member actuation algorithm andknife member actuation algorithm may be adjusted independently of themovable member actuation algorithm.

With trocar (642) in the closed position, control unit (672) may controlmotor unit (660) to initiate an adjusted actuation of staple drivermember to drive staples into clamped tissue. In some versions, thestaple member actuation algorithm and the knife member actuationalgorithm may be adjusted in a similar manner based on the samedifference value determined by control module (672) in connection withactuation of the monitored movable member. It will be understood thatcalibration of all three actuation algorithms ensures preciselongitudinal actuation of anvil (650), the staple driver member, and theknife member of instrument (600). The movable member (e.g. trocar (642),anvil (650), or trocar actuator (662)), staple driver member, and knifemember are operatively coupled with motor unit (660) and are actuatableindependently of one another by motor unit (660).

After executing the adjusted closure rate and/or closure stroke, method(800) may include actuating a staple driver member (not shown butsimilar to staple driver member (350)) to drive staples into clampedfirst and second tissue layers (T1, T2) using the adjusted closure rateand/or closure stroke. For example, the staple driver member may beactuated according to a staple closure stroke, a staple closure rate,and a staple pause sequence using staple actuator (664) thatincorporates the adjusted closure stroke and the initial tissue contactposition as described above.

Similarly, method (800) may also include actuating a knife member (notshown but similar to knife member (340)) to cut clamped tissue using theadjusted closure rate and/or closure stroke. For example, control module(672) may control motor unit (660) to initiate an adjusted actuation ofknife member to cut clamped tissue in response to both initial tissuecontact position (δ_(FC)) and gap formed between anvil (650) andopposing deck surface (644). More specifically, knife member may beactuated according to a knife closure stroke, a knife closure rate, anda knife pause sequence that incorporates adjusted closure stroke andinitial tissue contact position (δ_(FC)). Alternatively, knife membermay be actuated according to a knife closure stroke, a knife closurerate, and a knife pause sequence that incorporates adjusted closurestroke, initial tissue contact position (δ_(FC)), as well as the stapleclosure stroke, the staple closure rate, and the staple pause sequencedescribed above. As a result, knife member actuation algorithm wouldtake into account both the movable member actuation algorithm and thestaple member actuation algorithm.

Step (816) may include control module (672) controlling motor unit (660)to adjust each of adjusted closure rate, adjusted closure stroke, and aclosure pause based on closure data of sensor assembly (674)communicated to control module (672), where closure pause is a timeperiod when anvil (650) and opposing deck surface (644) do not movetoward the closed position. In other words, closure stroke, closurerate, and closure pauses may be incorporated into knife member and thestaple member actuation algorithm based on closure stroke and the firstcontact tissue position.

It will be appreciated that the actuation rates of one or more actuators(662, 664, 666) may be controlled based on additional factors as well,such as a size of stapling head assembly (640) or a target tissue gapspecified by a user via user interface (616). By way of example only,control module (672) may decrease the actuation rates of one or moreactuators (662, 664, 666) in the presence of a stapling head assembly ofa relatively larger diameter; and increase the actuation rates of one ormore actuators (662, 664, 666) in the presence of a stapling headassembly (640) of a relatively smaller diameter. Additionally, controlmodule (672) may decrease the actuation rates of one or more actuators(662, 664, 666) for larger tissue gaps and increase the actuation ratesof one or more actuators (662, 664, 666) for smaller tissue gaps, asdescribed in greater detail above.

C. Second Exemplary Method to Adjust Closure Rate

A second exemplary method (1000) of operating a powered surgicalstapler, such as circular surgical stapling instrument (600), is shownand described with reference to FIGS. 15A-15B. Particularly, FIGS.15A-15B show diagrammatic views of method (1000) for calibrating aclosure rate of a movable member of circular stapler of FIG. 9 byadjusting actuation algorithms executed by the control system (670) ofFIG. 10. FIG. 15A shows a first portion of method (1000) and FIG. 15Bshows a second portion of method (1000). According to method (1000),anvil closure rate varies based on a gap remaining when sensing theinitial tissue contact position and varies closure rate based on rate ofcurrent increased sensed by motor unit (660) closing anvil (650) usingtrocar actuator (662). Trocar (642) is actuatable between an openposition for receiving at least first and second tissue layers (T1, T2),a partially closed position, and the closed position, where at leastfirst and second tissue layers (T1, T2) are compressed together.

As shown in FIG. 15A, method (1000) begins at step (1002) with aninitiating event, which may be an actuation of closure trigger (624)following attachment of anvil (650) to trocar (642) during a surgicalprocedure. In response to the initiating event, control module (672)executes the stored movable member actuation algorithm at step (1004) toactivate motor unit (660) to actuate trocar actuator (662) proximally totransition anvil (650) toward the closed state. At step (1004), method(1000) includes control module (672) controlling motor unit (660) toactuate trocar (642) to move anvil (650) from the open position towardsthe partially closed position. Prior to or during execution of themovable member actuation algorithm, control module (672) determines thata monitored movable member (one of trocar actuator (662), trocar (642),or anvil (650)) is in a predetermined position, e.g. via detection bysensor assembly (674), for example using position sensor (680). By wayof example only, the predetermined position may correspond to anvil(650) in a fully open state.

At step (1006), method (1000) includes sensing a gap formed betweenanvil (650) and opposing deck surface (644) as trocar (642) moves fromthe open position towards the partially closed position at a first timeusing position sensor (680) of sensor assembly (674). The partiallyclosed position may be a predetermined position (e.g. quick close gap(δ_(QC))) or the initial tissue contact position shown in FIG. 13. Asshown, the initial tissue contact position is defined as the positionwhen first and second tissue layers (T1, T2) are fully approximated butnot yet compressed together. In the initial tissue contact position,initial tissue contact gap (δ_(FC)) is defined between deck surface(644) or anvil (650). With further reference to FIGS. 13 and 14, gap(δ_(QC), δ_(FC)) shrinks as movable member moves from the open positiontowards the partially closed position. Similar to step (1006), method(1000) also includes step (1008) sensing the gap formed between anvil(650) and opposing deck surface (644) using position sensor (680) ofsensor assembly (674) at a second time, after the first time, usingsensor assembly (674) as the movable member moves from the open positiontowards the closed position.

Position sensor (680) of sensor assembly (674) is in communication withcontrol module (672), which is in communication with motor unit (660) toaffect trocar actuator (662). Control module (672) may determine presentlongitudinal displacement of anvil (650) relative to deck surface (644)based on a signal provided by position sensor (680). As shown in FIG.13, position sensor (680) includes first and second sensor portions(682, 684), where first sensor portion (682) is disposed on anvil (650)and second sensor portion (684) is disposed on deck surface (644). Atstep (1010), method (1000) also includes communicating gap data obtainedfrom position sensor (680) of sensor assembly (674) to control module(672).

At step (1012), control module (672) compares the current closure rateof the monitored movable member observed by control module (672), viaposition sensor (680), to the closure rate stored by control module(672). Control module (672) determines at step (1012) whether there is adifference between the present closure rate and the closure rateobtained using gap data. If the values are equal or within apredetermined acceptable range of one another such that there is nosignificant difference, control module (672) proceeds to step (1014) tocontinues to execute the current algorithm in response to useractuations of closure trigger (624) and firing trigger (626). Method(800) may loop back to sense gap data at respective times as discussedabove with reference to steps (1006, 1008), such that method (1000)continues.

Alternatively, if control module (672) determines that there is asignificant difference between the values, control module (672) proceedsto step (1016) to adjust the closure rate to a first adjusted closurerate based on the determined difference. The first adjusted closure rateis speed at which gap (δ_(QC), δ_(FC)) formed between anvil (650) andopposing deck surface (644) shrinks moving toward the partially closedposition. In other words at step (1016), method (1000) also includescontrolling motor unit (660) to adjust the closure rate based on gapdata from sensor assembly (674) communicated to control module (672) astrocar (642) is moved from the open position to the partially closedposition. Adjusting the closure rate may improve compression of firstand second tissue layers (T1, T2) relative to a user selected staplesize. It is also envisioned that the closure stroke may be adjustedusing the gap data, in a similar manner to adjusting the closure rate tothe first adjusted closure rate.

At step (1020), method (800) includes determining with control module(672) whether the movable member has reached the partially closedposition. The partially closed position may be a predetermined position(e.g. quick close gap (δ_(QC))) or the initial tissue contact positionshown in FIG. 13. If yes, method (800) may move to step (1022) of FIG.15B once the partially closed position is reached with using theadjusted closure rate. This determination may be based on the gap dataobtained from position sensor (680).

At step (1024), method (1000) includes control module (672) controllingmotor unit (660) to actuate trocar (642) to move anvil (650) from thepartially closed position towards the closed position. At step (1026),method (1000) also includes sensing current data at a third time usingsensor assembly (674), where current data includes current drawn bymotor unit (660) as trocar (642) is moved from the partially closedposition to the closed position (δ_(AT1)). Similarly, at step (1028),method (1000) also includes sensing current data at a fourth time usingsensor assembly (674), where current data includes current drawn bymotor unit (660) as trocar (642) is moved from the partially closedposition to the closed position (δ_(AT1)). The closure of anvil (650)against a structure induces a longitudinal extension force in anvil(650), trocar (642), and trocar actuator (662) that makes furtherproximal retraction of these closure components by motor unit (660) moredifficult, thus increasing the electrical current force of motor unit(660). As a result, the first adjusted closure rate may be increased ordecreased in response to detection by current sensor (676) of theincrease in electrical current drawn by motor unit (660).

This increase in axial force (F_(A)) may be detected by one or moresensors of sensor assembly (674) in the form of current sensor (676) orforce sensor (678) that communicate with control module (672) as shownin FIG. 13. Axial force (F_(A)) may be exerted on trocar actuator (662)(and thus also anvil (650) and trocar (642)), or may be an electricalcurrent drawn by motor unit (660) while actuating trocar actuator (662).Control module (672) may determine that axial force (F_(A)) on anvil(650) has changed based on the current data provided by force sensor(678) that indicates an increase in axial force (F_(A)) exerted ontrocar actuator (662) (and thus also anvil (650) and trocar (642)). Theaxial force (F_(A)) on anvil (650) is proportional to electrical currentdrawn by motor unit (660) in moving from the open position to the closedposition. As a result, force sensor (678) may also produce the currentdata. At step (1030), method (1000) also includes communicating thecurrent data obtained from sensor assembly (674) (e.g. current sensor(676) or force sensor (678)) to control module (672).

At step (1032), control module (672) compares the closure rate observedby control module (672) using current sensor (676) or force sensor(678), to the first adjusted closure rate stored by control module(672). Control module (672) determines at step (1032) whether there is adifference between the closure rate obtained using current data and thepresent closure rate (e.g. first adjusted closure rate). If the valuesare equal or within a predetermined acceptable range of one another suchthat there is no significant difference, control module (672) proceedsto step (1034) to continue to execute the first adjusted closure rate.

Alternatively, if control module (672) determines that there is asignificant difference between the values, control module (672) proceedsto step (1036) to adjust the first adjusted closure rate to the secondadjusted closure rate based on the determined difference. The secondadjusted closure rate is the speed at which the gap formed between anvil(650) and opposing deck surface (644) shrinks moving toward the closedposition (shown by closed gap (δ_(AT1))). Adjusting the first adjustedclosure rate to the second adjusted closure rate may improve compressionof first and second tissue layers (T1, T2) relative to a user selectedstaple size.

At step (1038), method (1000) also includes controlling motor unit (660)using the second adjusted closure rate based on determination of controlmodule (672). At step (1040), method (1000) includes determining withcontrol module (672) whether the movable member (e.g. trocar (642),anvil (650), or trocar actuator (662)) has reached the closed position.If yes, method (1000) may move to step (1042) where the algorithm may beterminated once the closed position is reached with using the adjustedclosure rate. If no, method (1000) may loop back to sense current dataat respective times as discussed above with reference to steps (1026,1028), such that method (1000) continues.

As previously discussed, it may be beneficial to use one or more of thefirst and second adjusted closure rates obtained during the movablemember actuation algorithm, to affect the staple member actuationalgorithm and the knife member actuation algorithm. As such, thecorresponding staple member actuation algorithm and knife memberactuation algorithm may be adjusted appropriately based on theadjustments made to the movable member actuation algorithm via method(1000). Alternatively, the staple member actuation algorithm and knifemember actuation algorithm may be adjusted independently of the movablemember actuation algorithm.

IV. Exemplary Combinations

The following examples relate to various non-exhaustive ways in whichthe teachings herein may be combined or applied. The following examplesare not intended to restrict the coverage of any claims that may bepresented at any time in this application or in subsequent filings ofthis application. No disclaimer is intended. The following examples arebeing provided for nothing more than merely illustrative purposes. It iscontemplated that the various teachings herein may be arranged andapplied in numerous other ways. It is also contemplated that somevariations may omit certain features referred to in the below examples.Therefore, none of the aspects or features referred to below should bedeemed critical unless otherwise explicitly indicated as such at a laterdate by the inventors or by a successor in interest to the inventors. Ifany claims are presented in this application or in subsequent filingsrelated to this application that include additional features beyondthose referred to below, those additional features shall not be presumedto have been added for any reason relating to patentability.

EXAMPLE 1

A method of operating a powered surgical stapler that includes a motorunit, at least one movable member operatively coupled with the motorunit, a controller in communication with the motor unit, a sensorassembly in communication with the controller, an anvil, and an opposingdeck surface, wherein the movable member is actuatable between an openposition for receiving at least first and second layers of tissue and aclosed position where the at least first and second layers of tissue arecompressed together, the method comprising: (a) controlling the motorunit to actuate the movable member to move from the open positiontowards the closed position; (b) sensing closure data using the sensorassembly, wherein the closure data includes each of: (i) an initialtissue contact position, (ii) a gap formed between the anvil and theopposing deck surface as the movable member moves from the open positiontowards the closed position, and (iii) an axial force on the anvil asthe movable member moves from the open position towards the closedposition; (c) communicating the closure data of the sensor assembly tothe controller; (d) determining with the controller at least one of anadjusted closure rate or an adjusted closure stroke using the closuredata; and (e) controlling the motor unit using at least one of theadjusted closure rate or the adjusted closure stroke based on thedetermination of the controller.

EXAMPLE 2

The method of Example 1, wherein the adjusted closure rate is the speedat which the gap between the anvil and the opposing deck surface shrinksmoving toward the closed position, wherein the adjusted closure strokeis the longitudinal distance between the anvil and the opposing decksurface between the open and closed positions.

EXAMPLE 3

The method of any of the preceding Examples, wherein the initial tissuecontact position is the position when the at least first and secondlayers of tissue are fully approximated but not yet compressed together.

EXAMPLE 4

The method of any of the preceding Examples, wherein the at least onemovable member comprises a trocar actuator, a trocar, or the anvil.

EXAMPLE 5

The method of any of the preceding Examples, wherein the at least onemovable member further comprises a staple driver member, wherein the atleast one movable member further comprises a knife member, wherein themethod further comprises: (a) with the moveable member in the closedposition, controlling the motor unit to initiate an adjusted actuationof the staple driver member to drive staples into the clamped tissue inresponse to the both the initial tissue contact position and the gapformed between the anvil and the opposing deck surface; and (b)controlling the motor unit to initiate an adjusted actuation of theknife member to cut the clamped tissue in response to the both theinitial tissue contact position and the gap formed between the anvil andthe opposing deck surface.

EXAMPLE 6

The method of any of the preceding Examples, wherein determining withthe controller at least one of the adjusted closure rate or the adjustedclosure stroke using the closure data further comprises determining withthe controller the adjusted closure rate and the adjusted closure strokeusing the closure data, wherein controlling the motor unit using atleast one of the adjusted closure rate or the adjusted closure strokebased on the determination of the controller further comprisesdetermining with the controller the adjusted closure rate and theadjusted closure stroke using the closure data.

EXAMPLE 7

The method of Example 6, wherein controlling the motor unit to adjusteach of the closure rate and the closure stroke further comprisescontrolling the motor unit to adjust each of the adjusted closure rate,the adjusted closure stroke, and a closure pause based on the closuredata of the sensor assembly communicated to the controller, wherein theclosure pause is a time period when the anvil and the opposing decksurface do not move toward the closed position.

EXAMPLE 8

The method of any of Examples 1 through 4 and Examples 6 through 7,further comprising: (a) actuating the movable member to clamp tissueusing at least one of the adjusted closure rate or the adjusted closurestroke; (b) actuating a staple driver member to drive staples into theclamped tissue; and (c) actuating a knife member to cut the clampedtissue.

EXAMPLE 9

The method of Example 8, wherein the closure member, the staple drivermember, and the knife member are operatively coupled with the motor unitand are actuatable independently of one another by the motor unit.

EXAMPLE 10

The method of any of Examples 8 through 9, wherein actuating the stapledriver member further comprises actuating the staple driver memberaccording to a staple closure stroke, a staple closure rate, and astaple pause sequence that incorporates the adjusted closure stroke andthe initial tissue contact position, wherein actuating the knife memberfurther comprises actuating the knife member according to a knifeclosure stroke, a knife closure rate, and a knife pause sequence thatincorporates the adjusted closure stroke and the initial tissue contactposition.

EXAMPLE 11

The method of Example 10, wherein actuating the knife member furthercomprises actuating the knife member according to the knife closurestroke, the knife closure rate, and the knife pause sequence thatincorporates the adjusted closure stroke, the initial tissue contactposition, the staple closure stroke, the staple closure rate, and thestaple pause sequence.

EXAMPLE 12

The method of any of the preceding Examples, wherein the sensor assemblycomprises a force sensor operatively coupled with the one of the anvilor the trocar, wherein the method further comprises determining with thecontroller that the axial force on the anvil has changed based on theclosure data provided by the force sensor that indicates an increase inlongitudinal force exerted on the movable member.

EXAMPLE 13

The method of any of the preceding Examples, wherein the sensor assemblycomprises a current sensor operatively coupled with the motor unit,wherein the method further comprises determining with the controllerthat the axial force on the anvil has increased based on the closuredata provided by the current sensor that indicates an increase inelectrical current drawn by the motor unit.

EXAMPLE 14

The method of any of the preceding Examples, wherein controlling themotor unit using at least one of the adjusted closure rate or theadjusted closure stroke further comprises decreasing the adjustedclosure rate or the adjusted closure stroke in response to detection bythe current sensor of an increase in the electrical current drawn by themotor unit

EXAMPLE 15

The method of any of the preceding Examples, wherein the sensor assemblycomprises a position sensor operatively coupled with at least one of theanvil or the trocar, wherein the method further comprises determiningwith the controller the actual longitudinal displacement of the anvilrelative to the deck surface based on the closure data provided by theposition sensor.

EXAMPLE 16

A method of operating a powered surgical stapler that includes a motorunit, at least one movable member operatively coupled with the motorunit, a controller in communication with the motor unit, and a sensorassembly in communication with the controller, an anvil, and an opposingdeck surface, wherein the movable member is actuatable between an openposition for receiving at least first and second layers of tissue and aclosed position where the at least first and second layers of tissue arecompressed together, the method comprising: (a) controlling the motorunit to actuate the movable member to move from the open positiontowards the closed position; (b) sensing closure data using the sensorassembly, wherein the closure data includes at least one of: (i) aninitial tissue contact position defined by when the at least first andsecond layers of tissue are approximated but not yet compressedtogether, (ii) a gap formed between the anvil and the opposing decksurface as the movable member moves from the open position towards theclosed position, and (iii) an axial force on the anvil as the movablemember moves from the open position towards the closed position; (c)communicating the closure data of the sensor assembly to the controller;(d) determining with the controller an adjusted closure rate and anadjusted closure stroke using the closure data; and (e) controlling themotor unit using the adjusted closure rate and the adjusted closurestroke based on the determination of the controller, wherein theadjusted closure rate is the speed at which the gap formed between theanvil and the opposing deck surface move toward the closed position,wherein the adjusted closure stroke is the longitudinal distance betweenthe anvil and the opposing deck surface between the open and closedpositions.

EXAMPLE 17

The method of Example 16, wherein the closure data includes each of: theinitial tissue contact position, the position of the anvil relative tothe opposing deck surface, and the axial force on the anvil.

EXAMPLE 18

The method of any of Examples 16 through 17, further comprising: (a)actuating the movable member to clamp tissue using at least one of theadjusted closure rate or the adjusted closure stroke; (b) actuating astaple driver member to drive staples into the clamped tissue; and (c)actuating a knife member to cut the clamped tissue, wherein actuatingthe staple driver member further comprises actuating the staple drivermember according to a staple closure stroke, a staple closure rate, anda staple pause sequence that incorporates the adjusted closure strokeand the initial tissue contact position, wherein actuating the knifemember further comprises actuating the knife member according to a knifeclosure stroke, a knife closure rate, and a knife pause sequence thatincorporates the adjusted closure stroke and the initial tissue contactposition.

EXAMPLE 19

A method of operating a powered surgical stapler that includes a motorunit, at least one movable member operatively coupled with the motorunit, a controller in communication with the motor unit, a sensorassembly in communication with the controller, an anvil operativelycoupled with the movable member, and an opposing deck surface, whereinthe movable member is actuatable between an open position for receivingat least first and second layers of tissue, a partially closed position,and a closed position where the at least first and second layers oftissue are compressed together, the method comprising: (a) controllingthe motor unit to actuate the movable member to move from the openposition towards the partially closed position; (b) sensing gap datausing the sensor assembly, wherein the gap data includes a gap formedbetween the anvil and the opposing deck surface as the movable membermoves from the open position towards the partially closed position; (c)communicating the gap data of the sensor assembly to the controller; (d)determining with the controller a first closure rate using the gap data;(e) controlling the motor unit to adjust the first closure rate based onthe gap data of the sensor assembly communicated to the controller asthe movable member is moved from the open position to the partiallyclosed position, wherein the first closure rate is the speed at which agap formed between the anvil and the opposing deck surface shrinksmoving toward the partially closed position; (f) sensing current datausing the sensor assembly, wherein the current data includes currentdrawn by the motor unit as the movable member moves from the partiallyclosed position to the closed position; (g) communicating the currentdata of the sensor assembly to the controller; (h) determining with thecontroller a second closure rate using the current data; and (i)controlling the motor unit to adjust a second closure rate based on thecurrent data of the sensor assembly communicated to the controller,wherein the second closure rate is the speed at which the gap formedbetween the anvil and the opposing deck surface shrinks moving towardthe closed position.

EXAMPLE 20

The method of Example 19, wherein the partially closed position iseither a predetermined position or an initial tissue contact positionbased on a position of the anvil relative to the opposing deck surface,wherein the gap data further includes sensing the initial tissue contactposition defined by when the at least first and second layers of tissueare approximated but not yet compressed together.

EXAMPLE 21

A powered surgical stapler comprising: (a) a motor unit; (b) at leastone movable member operatively coupled with the motor unit, wherein themovable member is configured to be actuated at least between an openposition for receiving at least first and second layers of tissue and aclosed position where the at least first and second layers of tissue arecompressed together; (c) a sensor assembly configured to sense: (i) aninitial tissue contact position, and (iii) an axial force as the movablemember moves from the open position towards the closed position; and (d)a controller in communication with the motor unit and the sensorassembly, wherein the controller is configured to: (i) operate a controlprogram, and (ii) switch to an adaptive control program when thecontroller determines the initial tissue contact position has beenreached using data from the sensor assembly of an increase in axialforce.

EXAMPLE 22

The powered surgical stapler of Example 21, further comprising an anviland an opposing deck surface, wherein the sensor assembly is configureto sense a gap formed between the anvil and the opposing deck surface asthe movable member moves from the open position towards the closedposition, wherein the controller is configured to switch to the adaptivecontrol program when the controller determines the initial tissuecontact position has been reached using data from the sensor assembly ofthe increase in the axial force and by stroke location using the gapformed between the anvil and the opposing deck surface.

EXAMPLE 23

The powered surgical stapler of any one or more of Examples 21 through22, wherein the control program includes a closure rate and a closurestroke, wherein the adaptive closure program includes at least one of anadjusted closure rate different from the closure rate or an adjustedclosure stroke different from the closure stroke, wherein the controlleris configured to determine at least one of an adjusted closure rate oran adjusted closure stroke using the initial tissue contact position andthe axial force acquired by the sensor assembly.

EXAMPLE 24

The powered surgical stapler of Example 23, wherein the controller isconfigured to determine each of an adjusted closure rate or an adjustedclosure stroke using the initial tissue contact position and the axialforce acquired by the sensor assembly.

EXAMPLE 25

The powered surgical stapler of any of Examples 23 through 24, furthercomprising an anvil and an opposing deck surface, wherein the adjustedclosure rate is the speed at which a gap between the anvil and theopposing deck surface shrinks moving toward the closed position, whereinthe adjusted closure stroke is the longitudinal distance between theanvil and the opposing deck surface between the open and closedpositions.

EXAMPLE 26

The powered surgical stapler of any of Examples 21 through 25, whereinthe initial tissue contact position is the position when the at leastfirst and second layers of tissue are fully approximated but not yetcompressed together.

EXAMPLE 27

The powered surgical stapler of any of Examples 21 through 26, whereinthe at least one movable member comprises a trocar actuator, a trocar,or the anvil.

EXAMPLE 28

The powered surgical stapler of any of Examples 21 through 27, furthercomprising a staple driver member configured to drive staples into theclamped tissue, and a knife member configured to cut the clamped tissue.

EXAMPLE 29

The powered surgical stapler of any of Examples 21 through 28, whereinthe movable member, the staple driver member, and the knife member areoperatively coupled with the motor unit and are configured to beactuated independently of one another by the motor unit.

EXAMPLE 30

The powered surgical stapler of any of Examples 21 through 29, furthercomprising an anvil, wherein the sensor assembly comprises a forcesensor operatively coupled with the one of the anvil or the trocar,wherein the controller is configured to determine that the axial forceon the anvil has changed based on data provided by the force sensor thatindicates an increase in longitudinal force exerted on the movablemember.

EXAMPLE 31

The powered surgical stapler of any of Examples 21 through 30, whereinthe powered surgical stapler further comprises an anvil, wherein thesensor assembly comprises a current sensor operatively coupled with themotor unit, wherein the controller is configured to determine the axialforce on the anvil has increased based on data provided by the currentsensor that indicates an increase in electrical current drawn by themotor unit.

EXAMPLE 32

The powered surgical stapler of any of Examples 21 through 31, whereinthe powered surgical stapler further comprises an anvil, a trocar, and adeck surface, wherein the sensor assembly comprises a position sensoroperatively coupled with at least one of the anvil or the trocar,wherein the controller is configured to determine actual longitudinaldisplacement of the anvil relative to the deck surface based on closuredata provided by the position sensor.

V. Miscellaneous

It should also be understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Theabove-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of the claims.

Furthermore, any one or more of the teachings herein may be combinedwith any one or more of the teachings disclosed in U.S. Pat. App. No.[Atty. Ref. END9128USNP1], entitled “Method for Calibrating Movements ofActuated Members of Powered Surgical Stapler,” filed on even dateherewith; U.S. Pat. App. No. [Atty. Ref. END9129USNP1], entitled “Methodfor Controlling Cutting Member Actuation for Powered Surgical Stapler,”filed on even date herewith; and U.S. Pat. App. No. [Atty. Ref.END9142USNP1], entitled “Anvil Retention and Release Features forPowered Circular Surgical Stapler,” filed on even date herewith. Thedisclosure of each of these U.S. patent applications is incorporated byreference herein.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Versions of the devices described above may have application inconventional medical treatments and procedures conducted by a medicalprofessional, as well as application in robotic-assisted medicaltreatments and procedures. By way of example only, various teachingsherein may be readily incorporated into a robotic surgical system suchas the DAVINCI™ system by Intuitive Surgical, Inc., of Sunnyvale, Calif.

Versions described above may be designed to be disposed of after asingle use, or they can be designed to be used multiple times. Versionsmay, in either or both cases, be reconditioned for reuse after at leastone use. Reconditioning may include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, someversions of the device may be disassembled, and any number of theparticular pieces or parts of the device may be selectively replaced orremoved in any combination. Upon cleaning and/or replacement ofparticular parts, some versions of the device may be reassembled forsubsequent use either at a reconditioning facility, or by a userimmediately prior to a procedure. Those skilled in the art willappreciate that reconditioning of a device may utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

By way of example only, versions described herein may be sterilizedbefore and/or after a procedure. In one sterilization technique, thedevice is placed in a closed and sealed container, such as a plastic orTYVEK bag. The container and device may then be placed in a field ofradiation that can penetrate the container, such as gamma radiation,x-rays, or high-energy electrons. The radiation may kill bacteria on thedevice and in the container. The sterilized device may then be stored inthe sterile container for later use. A device may also be sterilizedusing any other technique known in the art, including but not limited tobeta or gamma radiation, ethylene oxide, or steam.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometrics, materials, dimensions, ratios, steps,and the like discussed above are illustrative and are not required.Accordingly, the scope of the present invention should be considered interms of the following claims and is understood not to be limited to thedetails of structure and operation shown and described in thespecification and drawings.

I/We claim:
 1. A method of operating a powered surgical stapler thatincludes a motor unit, at least one movable member operatively coupledwith the motor unit, a controller in communication with the motor unit,a sensor assembly in communication with the controller, an anvil, and anopposing deck surface, wherein the movable member is actuatable betweenan open position for receiving at least first and second layers oftissue and a closed position where the at least first and second layersof tissue are compressed together, the method comprising: (a)controlling the motor unit to actuate the movable member to move fromthe open position towards the closed position; (b) sensing closure datausing the sensor assembly, wherein the closure data includes each of:(i) an initial tissue contact position, (ii) a gap formed between theanvil and the opposing deck surface as the movable member moves from theopen position towards the closed position, and (iii) an axial force onthe anvil as the movable member moves from the open position towards theclosed position; (c) communicating the closure data of the sensorassembly to the controller; (d) determining with the controller at leastone of an adjusted closure rate or an adjusted closure stroke using theclosure data; and (e) controlling the motor unit using at least one ofthe adjusted closure rate or the adjusted closure stroke based on thedetermination of the controller.
 2. The method of claim 1, wherein theadjusted closure rate is the speed at which the gap between the anviland the opposing deck surface shrinks moving toward the closed position,wherein the adjusted closure stroke is the longitudinal distance betweenthe anvil and the opposing deck surface between the open and closedpositions.
 3. The method of claim 1, wherein the initial tissue contactposition is the position when the at least first and second layers oftissue are fully approximated but not yet compressed together.
 4. Themethod of claim 1, wherein the at least one movable member comprises atrocar actuator, a trocar, or the anvil.
 5. The method of claim 1,wherein the at least one movable member further comprises a stapledriver member, wherein the at least one movable member further comprisesa knife member, wherein the method further comprises: (a) with themoveable member in the closed position, controlling the motor unit toinitiate an adjusted actuation of the staple driver member to drivestaples into the clamped tissue in response to the both the initialtissue contact position and the gap formed between the anvil and theopposing deck surface; and (b) controlling the motor unit to initiate anadjusted actuation of the knife member to cut the clamped tissue inresponse to the both the initial tissue contact position and the gapformed between the anvil and the opposing deck surface.
 6. The method ofclaim 1, wherein determining with the controller at least one of theadjusted closure rate or the adjusted closure stroke using the closuredata further comprises determining with the controller the adjustedclosure rate and the adjusted closure stroke using the closure data,wherein controlling the motor unit using at least one of the adjustedclosure rate or the adjusted closure stroke based on the determinationof the controller further comprises determining with the controller theadjusted closure rate and the adjusted closure stroke using the closuredata.
 7. The method of claim 6, wherein controlling the motor unit toadjust each of the closure rate and the closure stroke further comprisescontrolling the motor unit to adjust each of the adjusted closure rate,the adjusted closure stroke, and a closure pause based on the closuredata of the sensor assembly communicated to the controller, wherein theclosure pause is a time period when the anvil and the opposing decksurface do not move toward the closed position.
 8. The method of claim6, further comprising: (a) actuating the movable member to clamp tissueusing at least one of the adjusted closure rate or the adjusted closurestroke; (b) actuating a staple driver member to drive staples into theclamped tissue; and (c) actuating a knife member to cut the clampedtissue.
 9. The method of claim 8, wherein the closure member, the stapledriver member, and the knife member are operatively coupled with themotor unit and are actuatable independently of one another by the motorunit.
 10. The method of claim 8, wherein actuating the staple drivermember further comprises actuating the staple driver member according toa staple closure stroke, a staple closure rate, and a staple pausesequence that incorporates the adjusted closure stroke and the initialtissue contact position, wherein actuating the knife member furthercomprises actuating the knife member according to a knife closurestroke, a knife closure rate, and a knife pause sequence thatincorporates the adjusted closure stroke and the initial tissue contactposition.
 11. The method of claim 10, wherein actuating the knife memberfurther comprises actuating the knife member according to the knifeclosure stroke, the knife closure rate, and the knife pause sequencethat incorporates the adjusted closure stroke, the initial tissuecontact position, the staple closure stroke, the staple closure rate,and the staple pause sequence.
 12. The method of claim 1, wherein thesensor assembly comprises a force sensor operatively coupled with theone of the anvil or the trocar, wherein the method further comprisesdetermining with the controller that the axial force on the anvil haschanged based on the closure data provided by the force sensor thatindicates an increase in longitudinal force exerted on the movablemember.
 13. The method of claim 1, wherein the sensor assembly comprisesa current sensor operatively coupled with the motor unit, wherein themethod further comprises determining with the controller that the axialforce on the anvil has increased based on the closure data provided bythe current sensor that indicates an increase in electrical currentdrawn by the motor unit.
 14. The method of claim 13, wherein controllingthe motor unit using at least one of the adjusted closure rate or theadjusted closure stroke further comprises decreasing the adjustedclosure rate or the adjusted closure stroke in response to detection bythe current sensor of an increase in the electrical current drawn by themotor unit.
 15. The method of claim 1, wherein the sensor assemblycomprises a position sensor operatively coupled with at least one of theanvil or a trocar, wherein the method further comprises determining withthe controller the actual longitudinal displacement of the anvilrelative to the deck surface based on the closure data provided by theposition sensor.
 16. A method of operating a powered surgical staplerthat includes a motor unit, at least one movable member operativelycoupled with the motor unit, a controller in communication with themotor unit, a sensor assembly in communication with the controller, ananvil, and an opposing deck surface, wherein the movable member isactuatable between an open position for receiving at least first andsecond layers of tissue and a closed position where the at least firstand second layers of tissue are compressed together, the methodcomprising: (a) controlling the motor unit to actuate the movable memberto move from the open position towards the closed position; (b) sensingclosure data using the sensor assembly, wherein the closure dataincludes at least one of: (i) an initial tissue contact position definedby when the at least first and second layers of tissue are approximatedbut not yet compressed together, (ii) a gap formed between the anvil andthe opposing deck surface as the movable member moves from the openposition towards the closed position, and (iii) an axial force on theanvil as the movable member moves from the open position towards theclosed position; (c) communicating the closure data of the sensorassembly to the controller; (d) determining with the controller anadjusted closure rate and an adjusted closure stroke using the closuredata; and (e) controlling the motor unit using the adjusted closure rateand the adjusted closure stroke based on the determination of thecontroller, wherein the adjusted closure rate is the speed at which thegap formed between the anvil and the opposing deck surface move towardthe closed position, wherein the adjusted closure stroke is thelongitudinal distance between the anvil and the opposing deck surfacebetween the open and closed positions.
 17. A powered surgical staplercomprising: (a) a motor unit; (b) at least one movable memberoperatively coupled with the motor unit, wherein the movable member isconfigured to be actuated at least between an open position forreceiving at least first and second layers of tissue and a closedposition where the at least first and second layers of tissue arecompressed together; (c) a sensor assembly configured to sense: (i) aninitial tissue contact position, and (iii) an axial force as the movablemember moves from the open position towards the closed position; and (d)a controller in communication with the motor unit and the sensorassembly, wherein the controller is configured to: (i) operate a controlprogram, and (ii) switch to an adaptive control program when thecontroller determines the initial tissue contact position has beenreached using data from the sensor assembly of an increase in axialforce.
 18. The powered surgical stapler of claim 17, further comprisingan anvil and an opposing deck surface, wherein the sensor assembly isconfigure to sense a gap formed between the anvil and the opposing decksurface as the movable member moves from the open position towards theclosed position, wherein the controller is configured to switch to theadaptive control program when the controller determines the initialtissue contact position has been reached using data from the sensorassembly of the increase in the axial force and by stroke location usingthe gap formed between the anvil and the opposing deck surface.
 19. Thepowered surgical stapler of claim 17, wherein the control programincludes a closure rate and a closure stroke, wherein the adaptiveclosure program includes at least one of an adjusted closure ratedifferent from the closure rate or an adjusted closure stroke differentfrom the closure stroke, wherein the controller is configured todetermine at least one of an adjusted closure rate or an adjustedclosure stroke using the initial tissue contact position and the axialforce acquired by the sensor assembly.
 20. The powered surgical staplerof claim 19, wherein the controller is configured to determine each ofan adjusted closure rate or an adjusted closure stroke using the initialtissue contact position and the axial force acquired by the sensorassembly.